Google, while struggling to remove bogus listings from the search engine's results, is itself hosting far more spam links than any other company, according to a rival's study. Microsoft researchers, in an exhaustive study of unethical web marketing, have concluded that more spam links appear on Google's Blogspot blog publishing service than the next ten sites put together.

"The first one is blogspot.com, with 3.882 appearances, which is an order of magnitude higher than the others in the chart," says the Microsoft Research report, which was mentioned in today's New York Times. "Typically, spammers create spam blogs... and use these doorway URLs to spam the comment area of other forums."

Blogspot, which offers free web space for sites made with Google's Blogger service, hosts millions of personal sites, and so it was always likely to attract its share of automated marketing messages. And Blogspot sites are open to comments, and therefore vulnerable to underhand web marketers who link to commercial sites while pretending to contribute to the discussion.

But the Google site appears to do a worse job in filtering out junk blogs than many competitors such as Tripod or Microsoft's own Spaces service. And automatically-generated marketing messages on Blogspot pollute search engines, including Google's own. Microsoft calculates that 77% of links on Blogspot tested were spam.

Google will be the most embarrassed by the spam research, because the Mountain View search engine has set itself up as an irreconcilable foe of crooked web marketers. But other big-name companies are also singled out. Looksmart, which once challenged internet portals such as Yahoo, has now morphed into one of the biggest middlemen in the spam marketing economy. And financial support for fake blogs, no doubt deniable, comes not just from offshore pharmacies but also from well-establishing online retail brands such as Dealtime and eBay's Shopping.com.