Online Advertising

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