Search engine optimization
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Search engine optimization
Relevance | Link campaign | Anchor text | Site map | Search engine results page | WebRank | Google consultant | SEO contest | Spamdexing
Search engine optimization (SEO) is a set of methods aimed at
improving the ranking of a website in search engine listings. The term
also refers to an industry of consultants who carry out optimization projects on behalf of
clients' sites. Practitioners may use "white hat SEO" (methods generally
approved by search engines, such as building content and improving site
quality), or "black hat SEO" (tricks such as cloaking and
spamdexing). White hatters charge that black hat methods are an
attempt to manipulate search rankings unfairly. Black hatters counter
that all SEO is an attempt to manipulate rankings, and that the
particular methods one uses to rank well are irrelevant.
Search engines display different kinds of listings in the
search engine results pages (SERPs), including:
pay-per-click
advertisements,
paid inclusion listings, and
organic search results. SEO is primarily concerned with advancing the goals
of a web site
by improving the number and position of its
organic search results for a wide variety of relevant
keywords. SEO
strategies can increase both the number and quality of visitors, where quality
means visitors who complete the action hoped for by the site owner (e.g.
purchase, sign up, learn something).
For competitive, high-volume search terms, the cost of
pay
per click advertising can be substantial. Ranking well in the organic search
results can provide the same targeted traffic at a potentially lower cost. Site
owners may choose to optimize their sites for organic search, if the cost of
optimization is less than the cost of advertising.
Not all sites have identical goals for search optimization. Some sites are
seeking any and all traffic, and may be optimized to rank highly for common
search phrase. A broad search optimization strategy can work for a site that has
broad interest, such as a
periodical, a directory, or site that displays advertising with a CPM revenue
model. In contrast, many businesses try to optimize their sites for large
numbers of highly specific keywords that indicate readiness to buy. Overly broad
search optimization can hinder marketing strategy by generating a large volume
of low-quality inquiries that cost money to handle, yet result in little
business. Focusing on desirable traffic generates better quality sales leads,
allowing the sales force to close more business.
History
Early search engines
SEO began in the mid-1990s, as the first search engines were cataloging the
early Web. Initially, all a webmaster needed to do was submit a site to the
various engines which would run spiders, programs to "crawl" the site, and store
the collected data. The search engines then sorted the information by topic, and
served results based on pages they had spidered. As the number of documents
online kept growing, and more webmasters realized the value of organic search
listings, so popular search engines began to sort their listings so they could
display the most relevant pages first. This was the start of a search engine
versus webmaster
game that continues to this day.
At first search engines were guided by the webmasters themselves. Early
versions of search
algorithms relied on webmaster-provided information such as category and keyword
meta tags. Meta tags provided a guide to each page's content. When some
webmasters began to abuse meta tags, causing their pages to rank for irrelevant
searches, search engines abandoned their consideration of Meta tags and instead
developed more complex ranking algorithms, taking into account factors that were more diverse, including:
- Text within the title tag
- Domain name
-
URL directories and file names
-
HTML tags: headings, bold and emphasized text
-
Keyword density
- Keyword proximity
-
Alt attributes for images
- Text within NOFRAMES tags
By relying so extensively on factors that were still within the webmasters'
exclusive control, search engines continued to suffer from abuse and ranking
manipulation. In order to provide better results to their users, search engines
had to adapt to ensure their SERPs showed the most relevant search results,
rather than useless pages stuffed with keywords by unscrupulous webmasters. This
led to the rise of a new kind of search engine.
Organic search engines
Google was started by two PhD students at Stanford University, Sergey Brin
and Larry Page, and brought a new concept to evaluating web pages. This concept, called
PageRank,
has been from the start important to the Google algorithm
[1]. PageRank relies heavily on incoming links and
uses the logic that each link to a page is a vote for that page's value. The
more incoming links a page had the more "worthy" it is. The value of each
incoming link itself varies directly based on the PageRank of the page it comes
from and inversely on the number of outgoing links on that page.
With help from PageRank, Google proved to be very good at serving relevant
results. Google became the most popular and successful search engine. Because
PageRank measured an off-site factor, Google felt it would be more difficult to
manipulate than on-page factors.
But manipulated it was. Webmasters had already developed link manipulation
tools and schemes to influence the Inktomi search engine. These methods proved
to be equally applicable to Google's algorithm. Many sites focused on
exchanging, buying, and selling links on a massive scale. PageRank's reliance on
the link as a vote of confidence in a page's value was undermined as many
webmasters sought to garner links purely to influence Google into sending them
more traffic, irrespective of whether the link was useful to human site
visitors.
It was time for Google—and other search engines—to look at a wider range of
off-site factors. There were other reasons to develop more intelligent
algorithms. The Internet was reaching a vast population of non-technical users
who were often unable to use advanced querying techniques to reach the
information they were seeking and the sheer volume and complexity of the indexed
data was vastly different from that of the early days. Search engines had to
develop predictive,
semantic, linguistic and heuristic
algorithms.
A proxy for the PageRank metric is still displayed in the
Google Toolbar, but PageRank is only one of more than 100 factors that
Google considers in ranking pages.
Today, most search engines keep their methods and ranking algorithms secret.
A search engine may use hundreds of factors in ranking the listings on its
SERPs; the factors themselves and the weight each carries may change
continually.
Much current SEO thinking on what works and what doesn't is largely
speculation and informed guesses. Some SEOs have carried out controlled
experiments to gauge the effects of different approaches to search optimization.
The following, though, are some of the considerations search engines could be
building into their algorithms, and the list of Google patents
[2] may give some indication as to what is in the pipeline:
- Age of site
- Length of time domain has been registered
- Age of content
- Regularity with which new content is added
- Age of link and reputation of linking site
- Standard on-site factors
- Negative scoring for on-site factors (for example, a dampening for sites
with extensive keyword meta tags indicative of having being SEO-ed)
- Uniqueness of content
- Related terms used in content (the terms the search engine associates as
being related to the main content of the page)
- Google Pagerank (Only used in Google's algorithm)
- External links, the anchor text in those external links and in the
sites/pages containing those links
- Citations and research sources (indicating the content is of research
quality)
- Stem-related terms in the search engine's database (finance/financing)
- Incoming backlinks and anchor text of incoming backlinks
- Negative scoring for some incoming backlinks (perhaps those coming from
low value pages, reciprocated backlinks, etc.)
- Rate of acquisition of backlinks: too many too fast could indicate
"unnatural" link buying activity
- Text surrounding outward links and incoming backlinks. A link following
the words "Sponsored Links" could be ignored
- Use of "rel=nofollow" to suggest that the search engine should ignore
the link
- Depth of document in site
- Metrics collected from other sources, such as monitoring how frequently
users hit the back button when SERPs send them to a particular page
- Metrics collected from sources like the
Google Toolbar,
Google
AdWords/Adsense
programs, etc.
- Metrics collected in data-sharing arrangements with third parties (like
providers of statistical programs used to monitor site traffic)
- Rate of removal of incoming links to the site
- Use of sub-domains, use of keywords in sub-domains and volume of content
on sub-domains… and negative scoring for such activity
- Semantic connections of hosted documents
- Rate of document addition or change
- IP of hosting service and the number/quality of other sites hosted on
that IP
- Other affiliations of linking site with the linked site (do they share
an IP? have a common postal address on the "contact us" page?)
- Technical matters like use of 301 to redirect moved pages, showing a 404
server header rather than a 200 server header for pages that don't exist,
proper use of
robots.txt
- Hosting uptime
- Whether the site serves different content to different categories of
users (cloaking)
- Broken outgoing links not rectified promptly
- Unsafe or illegal content
- Quality of HTML coding, presence of coding errors
- Actual click through rates observed by the search engines for listings
displayed on their SERPs
- Hand ranking by humans of the most frequently accessed SERPs
The relationship between SEO and the search engines
Search engine operators became interested in the SEO community in the late
1990s. A number of high profile SEO community leaders established contractual
relationships with search engines for advertising and consulting purposes. These
early contacts led to an amelioration of some hostile feelings between the
search optimization and search engineering communities.
In early 2000, search engines and SEO firms attempted to establish an
unofficial "truce."
There are several tiers of SEO firms, and the more reputable companies employ
content-based optimizations which meet with the search engines' (reluctant)
approval. These techniques include improvements to site navigation and
copywriting, designed to make websites more intelligible to search engine
algorithms.
Some search engines have also reached out to the SEO industry, and are
frequent sponsors and guests at SEO conferences 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.
Getting into search engines' listings
New sites do not need to be "submitted" to search engines to be listed. A
simple link from an established site will get the search engines to visit the
new site and spider its contents. It is rarely more than a few days from the
acquisition of the link to all the main search engine spiders visiting and
indexing the new site.
Once the search engine has found the new site, it will generally visit and
index all the pages on the site, as long as all the pages are linked to with
standard <a href> hyperlinks. Pages which are accessible only through Flash or
Javascript links may not be findable by the spiders.
Webmasters can instruct spiders to not index certain files or directories
through the standard
robots.txt
file in the root directory of the domain. Standard practice requires a search
engine to check this file upon visiting the domain. The web developer can use
this feature to prevent pages such as shopping carts or other dynamic,
user-specific content from appearing in search engine results.
For those search engines who have their own paid submission (like Yahoo), it
may save some time to pay a nominal fee for submission.
White hat methods
So-called "white hat" methods of SEO involve following the search engines'
guidelines as to what is and what isn't acceptable. Their advice generally is to
create content for the user, not the search engines; to make that content easily
accessible to their spiders; and to not try to game their system. Often
webmasters make critical mistakes when designing or setting up their web sites,
inadvertently "poisoning" them so that they will not rank well. White hat SEO
attempts to discover and correct mistakes, such as machine-unreadable menus,
broken links, temporary redirects, or a generally poor navigation structure that
places pages too many clicks from the home page.
Because search engines are text-centric, many of the same methods that are
useful for
web accessibility are also advantageous for SEO. Methods are available for
optimizing graphical content, including ALT attributes, and adding a text
caption. Even Flash animations can be optimized by using an OBJECT element that
contains equivalent HTML content
[3].
Some methods considered proper by the search engines:
- Using a short and relevant title to name each page.
- Editing web pages to replace vague wording with specific terminology
that is relevant to the subject of the page.
- Increasing the amount of original content on a site.
- Using a reasonably-sized, accurate description meta tag without
excessive use of keywords, exclamation marks or off topic terms.
- Ensuring that all pages are accessible via regular links, and not only
via
Java, Javascript or Macromedia Flash applications; this can be done through the use of a
page listing all the contents of the site (a
Site map)
- Developing links via natural methods: Google doesn't elaborate on this
somewhat vague guideline. Dropping an email to a fellow webmaster telling
him about a great article you've just posted, and requesting a link, is most
likely acceptable.
- Participating in a
web ring
with other web sites as long as the other websites are independent, share
the same topic, and are of comparable quality.
Black hat methods
- Main article:
Spamdexing
Spamdexing is the promotion of irrelevant, chiefly commercial, pages through
deceptive techniques and the abuse of the search algorithms. Many search
engine administrators consider any form of search engine optimization used to
improve a website's page rank as spamdexing. However, over time a widespread
consensus has developed in the industry as to what are and are not acceptable
means of boosting one's search engine placement and resultant traffic.
As search engines operate in a highly automated way it is often possible for
webmasters to use methods and tactics not approved by search engines to gain
better ranking. These methods often go unnoticed unless an employee from the
search engine manually visits the site and notices the activity, or a change in
ranking algorithm causes the site to lose the advantage thus gained. Sometimes a
company will employ an SEO consultant
to evaluate competitor's sites, and report "unethical" optimization methods to
the search engines.
Spamdexing often gets confused with legitimate search engine optimization
techniques, which do not involve deceit. Spamming involves getting web sites
more exposure than they deserve for their keywords, leading to unsatisfactory
search results. Optimization involves getting web sites the rank they deserve on
the most targeted keywords, leading to satisfactory search experiences.
When discovered, search engines may take action against those found to be
using unethical SEO methods. In February 2006, Google removed both BMW Germany
and Ricoh Germany for use of these practices.[4]
Legal issues
In 2002, search engine manipulator SearchKing filed suit in an Oklahoma court
against the search engine Google. SearchKing's claim was that Google's tactics to prevent spamdexing constituted
an unfair business practice. This may be compared to lawsuits which email
spammers have filed against spam-fighters, as in various cases against MAPS and
other DNSBLs. In
January of 2003, the court pronounced a
summary judgment in Google's favor.
[5]
High quality web sites typically rank well
A webmaster who wants to maximize the value of a web site can read the
guidelines published by the search engines, as well as the coding guidelines
published by the World Wide Web Consortium. If the guidelines are followed, and the site
presents frequently updated, useful, original content, and a few meaningful,
useful inbound links are established, it is usually possible to obtain a
significant amount of organic search traffic.
When a site has useful content, other webmasters will naturally place links
to the site, increasing its PageRank and flow of visitors. When visitors
discover a useful web site, they tend to refer other visitors by emailing or
instant messaging links.
As a result, SEO practices that improve web site quality are likely to
outlive short term practices that simply seek to manipulate search rankings. The
top SEOs recommend targeting the same thing that search engines seek to promote:
relevant, useful content for their users.
See also
References
External links
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