An odd bug in Google's search algorithms appears to be benefiting XXX-rated websites.
Searches for impossible pages - such as the contradictory search term
-4^(1/4) which means "Find me pages containing a 1 next to a 4, but which do not contain a 4 - return web-page results liberally sprinkled with links to online grumble flicks.
The bug is also triggered by other such implausible query strings, such as "1 2" -1 and "1 2" -2, according to curious web surfers who stumbled upon the glitch.
Jeremy Hoffman, a Google software engineer, contributed to a Quora discussion thread that revealed the bug, and noted that contradictory searches should return zero results.
"However, we have uncovered a bug that causes some web pages to 'match' these contradictory queries. Since these are the only results that 'match' the query, they are the results that get shown," he said.
The most promising theory to surface on Quora suggests that porn sites are making use of anchor text containing the contradictory queries. The left-field search engine optimisation is apparently exploiting a bug even Google is only dimly aware about.
"Since a lot of porn terms are competitive, my bet is that they're driving up certain sites using obscure terms that no one will use to build the page rank of their video sites, which then pass their link authority to the real sites that they're trying to boost," writes Lisa Vaas in a post on Sophos' Naked Security blog covering the issue.
"People aren't likely to find and report your gibberish link farm if only robots ever see it. You then use the sites that have a high authority and rank for nonsense terms to built the authority of the stuff that you're really trying to promote."
Hoffman said the search engine giant is working on a fix. ®