PubSubs LinkRanks, released on Monday, measures strength, persistence and vitality of links that appear in the more than 16 million Web feeds the tracking service monitors.
LinkRanks differs from competing ranking systems on a number of fronts. Relying on a nightly analysis of Web feeds, PubSub calculates which blogs are the most influential, which are getting the most number of links, and which links come from the most influential sites.
Beyond that, PubSub provides a detailed set of data that shows, for each site referred to from a feed, for each day, how many people linked to that site, how many people linked out and how many entries were created on that site.
"We compute ranks on a daily basis," said CTO and Cofounder Bob Wyman. "We dont do what everybody else does: We dont just count up links to a site and say the guy with the most links has the most popular site. The reason is we have to recognize that not all links are created equal. A link from a popular and influential site is much more valuable than from a site nobodys every heard of."
The page ranking system Google uses to figure out the relevant of pages uses much the same logic, Wyman said.
PubSub also pays attention to a few other factors. On a particular day, if one site links to another multiple times, the service doesnt rank subsequent links as high as the first link. The reason for that, said Wyman, is that if someone links within a story, theyll typically link multiple times as they point to various aspects of the same site.
Also, new links are given higher ranking than older links. So as a link ages, its value is discounted.
Thats an attempt to prevent a Janet Jackson wardrobe malfunction type of situation, Wyman said. "When Janet Jackson had her wardrobe malfunction, a couple of sites quickly put up links to pictures of the events," he said. "As a result they earned a tremendous number of incoming links.
"They rapidly became the most influential site for Janet Jackson," he said. "The reality is that most of those sites had nothing to do with Janet Jackson and werent particularly interesting, either. But they had 10,000, 15,000 or more links. That may work in the Web world where people search for retrospective [ranking] in overall times. But most people care about who has the buzz today."
Instead of showing which sites are influential on a given day, LinkRanks shows which sites have been persistently influential over the prior 15 or 30 days. That shows which sites can maintain buzz, Wyman said.
"The most interesting sites are those who sustain the buzz over a 15- or 30-day period," he said. "Somebody whos at the top of the heap over the last 30 days, this is probably a site that bears your attention and deserves to be kept track of over time."
PubSub is demonstrating how LinkRanks can be used in its "Fashionable Blogs" list, which shows the rise and fall of influence and popularity among fashion bloggers. PubSub plans to partner with a variety of domain experts in the future to provide other such focused ranked lists of specialty blogs.
LinkRanks is available on PubSubs site. PubSub is offered by PubSub Concepts Inc., in New York.