An algorithm refers to the formula or process used to reach a certain outcome. In terms of online marketing, an algorithm is used by search engines to rank websites on search engine results pages (SERPs). Search algorithms find and return the content from across the web formulaically deemed most relevant to users’ queries. They relying on hundreds of signals related to a given page’s SEO-friendliness, increasingly including factors that indicate a page is valuable to searchers.

Search engines regularly update their algorithms to provide users with the most comprehensive and accurate results possible, and these updates necessitate consistent quality checks with respect to site content and overall SEO.

Algorithms and the rise of personal search

In the early days of search, engine-specific algorithms were fairly consistent for each user. A Google search from a computer in California would have likely produced identical results to one conducted from a computer in Boston.

As search has become the universal starting point to research, search developers have worked to tailor their SERPs to the person conducting the search. Information such as location, previous searches and web history now factor into search results as the engines attempt to provide the information most likely to help individual users. Content pages are even subject to preferential ranking if they have been shared by the friends/ online connections of searchers who are logged into their social accounts at the time of search (Facebook when using Bing and Google+ when using Google). Indeed, search algorithms have been updated to consider factors indicative of popular, useful content.

Algorithms and quality content assurance

Just as algorithms increasingly account for personal search history, they are constantly being tweaked to produce the most high-quality, relevant results.

Google is currently the leading search engine, garnering about two-thirds of the world’s search queries. The company has also been the most aggressive in retooling its search algorithms to ensure its SERPs provide users with the information most likely to answer their queries. One well-known signal for Google algorithms is PageRank, which measures the volume of quality links pointing to a page.

Among the major changes Google has made in 2011 is a stronger emphasis on rewarding websites that provide quality, original content. The first Panda algorithm update came in February and had negatively impacted low-quality content, while shooting more reliable information and websites up its rankings. The latest algorithm, Panda 2.5, rolled out in late September, and it resulted in major traffic losses for some websites and gains for others.

Executives at the second-leading search engine, Bing, have similarly suggested that their algorithms aim to give top rankings to web pages that have the highest-quality, SEO-friendly content. Bing’s Duane Forrester went as far as to remind marketers that “all SEO ranking signals revolve around content of some kind.”

Google Penguin Resources
Google Hummingbird Resources