Bizarre Google search bug benefits porn websites


Once upon a time in January, a Quora user asked,

What does -4^(1/4)" mean and why is it connected to porn?

Certainly, as of Tuesday morning, a Google search on the equation was still returning (in addition to the equation’s solution) sites with very XXX titles, top results including “Sleazy Riders Rachel Starr” and “Four Guys And A Hooker”.

(By the way, you should first note that any strings mentioned in this post are Not Safe For Work, and even if you’re at home, you should close your browser window before it burns a hole through your monitor.)


An anonymous Quora user noted that the equation can be translated into a contradictory search string, in that it translates into something along the lines of:

"Find me pages … containing a 1 next to a 4, but which do not contain a 4."

Anon also noted that the bug is triggered by other (but not all) contradictory search strings, such as

"1 2" -1

"1 2" -2

Porn search results

Jeremy Hoffman, a Google software engineer who works on search quality, chimed in, explaining that these types of contradictory searches should return zero results, since it’s impossible to satisfy both requirements, but there seems to be a bug that causes some very interesting pages to “match” both contradictory sides of the queries.

His explanation:

As a web search query, [-4^(1/4)] is interpreted like [-4 "1 4"], as in "Find me pages which contain a 1 next to a 4, but which do not contain a 4." This should return zero results, because it is impossible to satisfy both requirements. 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.

NBC News’s Devin Coldewey broke it down further, interpreting the bug as being caused by Google calculating the numerical query as it should, but also running it as a normal text search, “just in case”.

The text version of the search then turns the equation’s parentheses into quote marks, and the negative sign is used to exclude unwanted words from results, Coldewey says.

Another Quora user, J.C. Hewitt, pointed out that the porn sites are likely benefiting from the glitch by using anchor text containing the contradictory queries, given that such sites are “super-SEO’d,” he says:

It's likely that the linking pages use anchor text that contains that query. This is just my guess and how I would achieve this effect if I were a bad guy.

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.

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.

Google is working on a fix, Hoffman wrote. Google declined to comment to the news outlets that asked how that’s coming along.

Porn image from Shutterstock.