Microsoft researchers have published a paper describing a new method for determining which Web pages are the most relevant for a given keyword search query.

Google relies in part on its PageRank algorithm to determine what's relevant. Microsoft's answer to PageRank is BrowseRank.

The academic paper, "BrowseRank: Letting Web Users Vote for Page Importance," was co-authored by Microsoft researchers Bin Gao, Tie-Yan Liu, and Hang Li; Zhiming Ma of the Chinese Academy of Sciences; Yuting Liu from Beijing Jiaotong University; Shuyuan He from Peking University; and Nankai University's Ying Zhang.

PageRank treats Web links as votes for relevance. The paper's authors say PageRank can generate inaccurate results "because links can be easily added and deleted by Web content creators."

BrowseRank, Microsoft claims, can deliver better search results by measuring user behavior: the Web pages Internet users visit and the amount of time they remain at those pages.

"The more visits of the page made by the users and the longer time periods spent by the users on the page, the more likely the page is important," the paper states. "With this graph, we can leverage hundreds of millions of users' implicit voting on page importance."

The paper mentions that the data set used to test BrowseRank was cleansed to protect user privacy. "All possible privacy information was rigorously filtered out and the data was sampled and cleaned to remove bias as much as possible," it says.

And that's the only mention of privacy in the document.

But privacy almost certainly would be an issue for Microsoft, if it tried to implement this technique without some means of anonymization. Keeping records of every Web site that every Internet user visits, as a way to determine relevant search results, would have huge privacy implications.