PubSub LinkRanks

LinkRanks are our way of measuring the strength, persistence, and vitality of links appearing in sites that syndicate their content. When PubSub reads an entry from a syndication feed, it takes note of any URLs (technically, URIs) it sees. PubSub users can then utilize this link data when creating subscriptions to better express what they're looking for.

PubSub monitors millions of feeds. By generating a list of all the URLs contained in entries of each feed, it's possible to determine a site's relevance just from the number of incoming links it has. LinkRank goes one step further and calculates a score for each linking site. Sites are then scored based on the score of the sites that link to them.

Once all the sites have been ranked, they are divided into percentiles. PubSub users can tune their subscriptions with these percentiles, filtering out results from sites whose LinkRank is beneath a certain threshold or zeroing in on results from sites in the top 5% percent.

Not all sites will have a LinkRank. If a site hasn't published in the last 30 days or its feed isn't read by PubSub, it won't be considered during the LinkRank calculation. Other factors include whether or not a site has InLinks, and where those InLinks are from.

It's important to note that LinkRanks are just relative numbers. They will fluctuate from day to day for a given site based on the overall activity of the syndicated web (i.e. websites that syndicate their content via ATOM, RSS, or other formats). The percentile is the important number to keep in mind when examining a site.