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| Search Engine Optimization! |
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En:
Search engine optimization (SEO) is the process of improving the
volume or quality of traffic to a web site from search engines via
"natural" or un-paid ("organic" or "algorithmic") search results as
opposed to search engine marketing (SEM) which deals with paid
inclusion. Typically, the earlier (or higher) a site appears in the
search results list, the more visitors it will receive from the search
engine. SEO may target different kinds of search, including image
search, local search, and industry-specific vertical search engines.
This gives a web site web presence.
As an Internet marketing strategy, SEO considers how search engines work
and what people search for. Optimizing a website primarily involves
editing its content and HTML and associated coding to both increase its
relevance to specific keywords and to remove barriers to the indexing
activities of search engines.
The acronym "SEO" can also refer to "search engine optimizers," a term
adopted by an industry of consultants who carry out optimization
projects on behalf of clients, and by employees who perform SEO services
in-house. Search engine optimizers may offer SEO as a stand-alone
service or as a part of a broader marketing campaign. Because effective
SEO may require changes to the HTML source code of a site, SEO tactics
may be incorporated into web site development and design. The term
"search engine friendly" may be used to describe web site designs,
menus, content management systems, images, videos, shopping carts, and
other elements that have been optimized for the purpose of search engine
exposure.
Another class of techniques, known as black hat SEO or Spamdexing, use
methods such as link farms, keyword stuffing and article spinning that
degrade both the relevance of search results and the user-experience of
search engines. Search engines look for sites that employ these
techniques in order to remove them from their indices.
History
Webmasters and content providers began optimizing sites for search
engines in the mid-1990s, as the first search engines were cataloging
the early Web. Initially, all a webmaster needed to do was submit the
address of a page, or URL, to the various engines which would send a
spider to "crawl" that page, extract links to other pages from it, and
return information found on the page to be indexed.[1] The process
involves a search engine spider downloading a page and storing it on the
search engine's own server, where a second program, known as an indexer,
extracts various information about the page, such as the words it
contains and where these are located, as well as any weight for specific
words, and all links the page contains, which are then placed into a
scheduler for crawling at a later date.
Site owners started to recognize the value of having their sites highly
ranked and visible in search engine results, creating an opportunity for
both white hat and black hat SEO practitioners. According to industry
analyst Danny Sullivan, the phrase search engine optimization probably
came into use in 1997.[2]
Early versions of search algorithms relied on webmaster-provided
information such as the keyword meta tag, or index files in engines like
ALIWEB. Meta tags provide a guide to each page's content. But using meta
data to index pages was found to be less than reliable because the
webmaster's choice of keywords in the meta tag could potentially be an
inaccurate representation of the site's actual content. Inaccurate,
incomplete, and inconsistent data in meta tags could and did cause pages
to rank for irrelevant searches.[3] Web content providers also
manipulated a number of attributes within the HTML source of a page in
an attempt to rank well in search engines.[4]
By relying so much on factors such as keyword density which were
exclusively within a webmaster's control, early search engines suffered
from abuse and ranking manipulation. To provide better results to their
users, search engines had to adapt to ensure their results pages showed
the most relevant search results, rather than unrelated pages stuffed
with numerous keywords by unscrupulous webmasters. Since the success and
popularity of a search engine is determined by its ability to produce
the most relevant results to any given search, allowing those results to
be false would turn users to find other search sources. Search engines
responded by developing more complex ranking algorithms, taking into
account additional factors that were more difficult for webmasters to
manipulate.
Graduate students at Stanford University, Larry Page and Sergey Brin,
developed "backrub," a search engine that relied on a mathematical
algorithm to rate the prominence of web pages. The number calculated by
the algorithm, PageRank, is a function of the quantity and strength of
inbound links.[5] PageRank estimates the likelihood that a given page
will be reached by a web user who randomly surfs the web, and follows
links from one page to another. In effect, this means that some links
are stronger than others, as a higher PageRank page is more likely to be
reached by the random surfer.
Page and Brin founded Google in 1998. Google attracted a loyal following
among the growing number of Internet users, who liked its simple
design.[6] Off-page factors (such as PageRank and hyperlink analysis)
were considered as well as on-page factors (such as keyword frequency,
meta tags, headings, links and site structure) to enable Google to avoid
the kind of manipulation seen in search engines that only considered
on-page factors for their rankings. Although PageRank was more difficult
to game, webmasters had already developed link building tools and
schemes to influence the Inktomi search engine, and these methods proved
similarly applicable to gaming PageRank. Many sites focused on
exchanging, buying, and selling links, often on a massive scale. Some of
these schemes, or link farms, involved the creation of thousands of
sites for the sole purpose of link spamming.[7]
By 2004, search engines had incorporated a wide range of undisclosed
factors in their ranking algorithms to reduce the impact of link
manipulation. Google says it ranks sites using more than 200 different
signals.[8] The three leading search engines, Google, Yahoo and
Microsoft's Bing, do not disclose the algorithms they use to rank pages.
Notable SEOs, such as Rand Fishkin, Barry Schwartz, Aaron Wall and Jill
Whalen, have studied different approaches to search engine optimization,
and have published their opinions in online forums and blogs.[9][10] SEO
practitioners may also study patents held by various search engines to
gain insight into the algorithms.[11]
In 2005 Google began personalizing search results for each user.
Depending on their history of previous searches, Google crafted results
for logged in users.[12] In 2008 Bruce Clay, said that "ranking is dead"
because of personalized search. It would become meaningless to discuss
how a website ranked, because it's rank would potentially be different
for each user and each search.[13]
In 2007 Google announced a campaign against paid links that transfer
PageRank.[14] In 2009 Google disclosed that they had taken measures to
mitigate the effects of PageRank sculpting by use of the nofollow
attribute on links.[15]
Relationship with search engines
By 1997 search engines recognized that webmasters were making efforts to
rank well in their search engines, and that some webmasters were even
manipulating their rankings in search results by stuffing pages with
excessive or irrelevant keywords. Early search engines, such as Infoseek,
adjusted their algorithms in an effort to prevent webmasters from
manipulating rankings.[16]
Due to the high marketing value of targeted search results, there is
potential for an adversarial relationship between search engines and
SEOs. In 2005, an annual conference, AIRWeb, Adversarial Information
Retrieval on the Web,[17] was created to discuss and minimize the
damaging effects of aggressive web content providers.
SEO companies that employ overly aggressive techniques can get their
client websites banned from the search results. In 2005, the Wall Street
Journal reported on a company, Traffic Power, which allegedly used
high-risk techniques and failed to disclose those risks to its
clients.[18] Wired magazine reported that the same company sued blogger
and SEO Aaron Wall for writing about the ban.[19] Google's Matt Cutts
later confirmed that Google did in fact ban Traffic Power and some of
its clients.[20]
Some search engines have also reached out to the SEO industry, and are
frequent sponsors and guests at SEO conferences, chats, and seminars. In
fact, with the advent of paid inclusion, some search engines now have a
vested interest in the health of the optimization community. Major
search engines provide information and guidelines to help with site
optimization.[21][22][23] Google has a Sitemaps program[24] to help
webmasters learn if Google is having any problems indexing their website
and also provides data on Google traffic to the website. Google
guidelines are a list of suggested practices Google has provided as
guidance to webmasters. Yahoo! Site Explorer provides a way for
webmasters to submit URLs, determine how many pages are in the Yahoo!
index and view link information.
Methods
Main article: search engine optimization methods
[edit] Getting indexed
The leading search engines, such as Google and Yahoo!, use crawlers to
find pages for their algorithmic search results. Pages that are linked
from other search engine indexed pages do not need to be submitted
because they are found automatically. Some search engines, notably
Yahoo!, operate a paid submission service that guarantee crawling for
either a set fee or cost per click.[26] Such programs usually guarantee
inclusion in the database, but do not guarantee specific ranking within
the search results.[27] Two major directories, the Yahoo Directory and
the Open Directory Project both require manual submission and human
editorial review.[28] Google offers Google Webmaster Tools, for which an
XML Sitemap feed can be created and submitted for free to ensure that
all pages are found, especially pages that aren't discoverable by
automatically following links.[29]
Search engine crawlers may look at a number of different factors when
crawling a site. Not every page is indexed by the search engines.
Distance of pages from the root directory of a site may also be a factor
in whether or not pages get crawled.[30]
[edit] Preventing crawling
Main article: Robots Exclusion Standard
To avoid undesirable content in the search indexes, webmasters can
instruct spiders not to crawl certain files or directories through the
standard robots.txt file in the root directory of the domain.
Additionally, a page can be explicitly excluded from a search engine's
database by using a meta tag specific to robots. When a search engine
visits a site, the robots.txt located in the root directory is the first
file crawled. The robots.txt file is then parsed, and will instruct the
robot as to which pages are not to be crawled. As a search engine
crawler may keep a cached copy of this file, it may on occasion crawl
pages a webmaster does not wish crawled. Pages typically prevented from
being crawled include login specific pages such as shopping carts and
user-specific content such as search results from internal searches. In
March 2007, Google warned webmasters that they should prevent indexing
of internal search results because those pages are considered search
spam.[31]
[edit] Increasing prominence
A variety of other methods are employed to get a webpage shown up in the
searchs results. These include:
* Cross linking between pages of the same website. Giving more links to
main pages of the website, to increase PageRank used by search
engines.[32] Linking from other websites, including link farming and
comment spam.
* Writing content that includes frequently searched keyword phrase, so
as to be relevant to a wide variety of search queries.[33] Adding
relevant keywords to a web page meta tags, including keyword stuffing.
* URL normalization of web pages accessible via multiple urls, using the
"canonical" meta tag
White hat versus black hat
SEO techniques can be classified into two broad categories: techniques
that search engines recommend as part of good design, and those
techniques of which search engines do not approve. The search engines
attempt to minimize the effect of the latter, among them spamdexing.
Some industry commentators have classified these methods, and the
practitioners who employ them, as either white hat SEO, or black hat SEO.[35]
White hats tend to produce results that last a long time, whereas black
hats anticipate that their sites may eventually be banned either
temporarily or permanently once the search engines discover what they
are doing.[36]
An SEO technique is considered white hat if it conforms to the search
engines' guidelines and involves no deception. As the search engine
guidelines[21][22][23][37] are not written as a series of rules or
commandments, this is an important distinction to note. White hat SEO is
not just about following guidelines, but is about ensuring that the
content a search engine indexes and subsequently ranks is the same
content a user will see. White hat advice is generally summed up as
creating content for users, not for search engines, and then making that
content easily accessible to the spiders, rather than attempting to
trick the algorithm from its intended purpose. White hat SEO is in many
ways similar to web development that promotes accessibility,[38]
although the two are not identical.
Black hat SEO attempts to improve rankings in ways that are disapproved
of by the search engines, or involve deception. One black hat technique
uses text that is hidden, either as text colored similar to the
background, in an invisible div, or positioned off screen. Another
method gives a different page depending on whether the page is being
requested by a human visitor or a search engine, a technique known as
cloaking.
Search engines may penalize sites they discover using black hat methods,
either by reducing their rankings or eliminating their listings from
their databases altogether. Such penalties can be applied either
automatically by the search engines' algorithms, or by a manual site
review. Infamous examples are the February 2006 Google removal of both
BMW Germany and Ricoh Germany for use of deceptive practices.[39] and
the April 2006 removal of the PPC Agency BigMouthMedia.[40] All three
companies, however, quickly apologized, fixed the offending pages, and
were restored to Google's list.[41]
Many Web applications employ back-end systems that dynamically modify
page content (both visible and meta-data) and are designed to increase
page relevance to search engines based upon how past visitors reached
the original page. This dynamic search engine optimization and tuning
process can be (and has been) abused by criminals in the past.
Exploitation of Web applications that dynamically alter themselves can
be poisoned.
As a marketing strategy
Eye tracking studies have shown that searchers scan a search results
page from top to bottom and left to right (for left to right languages),
looking for a relevant result. Placement at or near the top of the
rankings therefore increases the number of searchers who will visit a
site.[43] However, more search engine referrals does not guarantee more
sales. SEO is not necessarily an appropriate strategy for every website,
and other Internet marketing strategies can be much more effective,
depending on the site operator's goals.[44] A successful Internet
marketing campaign may drive organic traffic to web pages, but it also
may involve the use of paid advertising on search engines and other
pages, building high quality web pages to engage and persuade,
addressing technical issues that may keep search engines from crawling
and indexing those sites, setting up analytics programs to enable site
owners to measure their successes, and improving a site's conversion
rate.[45]
SEO may generate a return on investment. However, search engines are not
paid for organic search traffic, their algorithms change, and there are
no guarantees of continued referrals. Due to this lack of guarantees and
certainty, a business that relies heavily on search engine traffic can
suffer major losses if the search engines stop sending visitors.[46] It
is considered wise business practice for website operators to liberate
themselves from dependence on search engine traffic.[47] A top-ranked
SEO blog Seomoz.org[48] has suggested, "Search marketers, in a twist of
irony, receive a very small share of their traffic from search engines."
Instead, their main sources of traffic are links from other websites.
International markets
Optimization techniques are highly tuned to the dominant search engines
in the target market. The search engines' market shares vary from market
to market, as does competition. In 2003, Danny Sullivan stated that
Google represented about 75% of all searches.[50] In markets outside the
United States, Google's share is often larger, and Google remains the
dominant search engine worldwide as of 2007.[51] As of 2006, Google had
an 85-90% market share in Germany.[52] While there were hundreds of SEO
firms in the US at that time, there were only about five in Germany.[52]
As of June 2008, the marketshare of Google in the UK was close to 90%
according to Hitwise.[53] That market share is achieved in a number of
countries.[54]
As of 2009, there are only a few large markets where Google is not the
leading search engine. In most cases, when Google is not leading in a
given market, it is lagging behind a local player. The most notable
markets where this is the case are China, Japan, South Korea, Russia and
Czech Republic where respectively Baidu, Yahoo! Japan, Naver, Yandex and
Seznam are market leaders.
Successful search optimization for international markets may require
professional translation of web pages, registration of a domain name
with a top level domain in the target market, and web hosting that
provides a local IP address. Otherwise, the fundamental elements of
search optimization are essentially the same, regardless of language.
Legal precedents
On October 17, 2002, SearchKing filed suit in the United States District
Court, Western District of Oklahoma, against the search engine Google.
SearchKing's claim was that Google's tactics to prevent spamdexing
constituted a tortious interference with contractual relations. On May
27, 2003, the court granted Google's motion to dismiss the complaint
because SearchKing "failed to state a claim upon which relief may be
granted."[55][56]
In March 2006, KinderStart filed a lawsuit against Google over search
engine rankings. Kinderstart's web site was removed from Google's index
prior to the lawsuit and the amount of traffic to the site dropped by
70%. On March 16, 2007 the United States District Court for the Northern
District of California (San Jose Division) dismissed KinderStart's
complaint without leave to amend, and partially granted Google's motion
for Rule 11 sanctions against KinderStart's attorney, requiring him to
pay part of Google's legal expenses.
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