Feedback from a "Looking at Links" workshop held at the Search Engine Strategies conference in San Jose, California. The article summarises what Google and Teoma reps had to say about how their respective search engines viewed links:
'Google essentially treats each link from one site to another as a vote for the site receiving the link (link popularity), but each vote is not created equal. Dulitz used a simple diagram to show that each page of a site only has one vote to give, so the more links to different sites on the same page the less of a vote each one receives. He also stated that links from higher quality sites carry more weight than those of lesser quality sites (e.g. sites with hidden links, involved in link farms, no incoming links, etc.). In addition, Google not only analyzes who is linking to whom, but they also analyze the text in and around the links to help determine the relevance of the pages receiving the links.'
'Teoma views the web as a global entity that contains many subject based web site communities. They study these subject communities and the manner in which they are interlinked within themselves and with each other to determine not only their link popularity, but also the subject and context of the involved sites. According to Gardi, Teoma is able to do this by using their unique method of ranking sites. He explained that rather than relying on general link popularity to determine results, their engine attempts to employ a "subject specific popularity" to locate the most popular sites within a specific subject community. This is done by first analyzing the web as a whole to identify subject communities. Teoma then employs link popularity within those communities to determine which sites are the "authorities" on the subject of the query and it's those sites that are returned as their results to a search.'