A user on Quora has uncovered a bug on Google search that will yield porn site results without actually searching for it. The bug was apparently uncovered via Google's ability to solve equations — entering them in a certain way causes the search engine to misinterpret your query. It's a result of the combination of impossible questions and what appears to be nefarious search engine optimization (SEO). It's important to note we haven't been able to replicate the bug with SafeSearch turned on and that a Google engineer has said the company will fix the problem

If it's not already abundantly clear, trying the following will result in not-safe-for-work web links, but here's what's happening. In the Quora example, searching for "-4^(1/4)" gives you Google's calculator with the correct answer, "-1.41421356237," but then Google provides a slew of porn links. Google is interpreting that equation as an impossible query, as Google engineer Jeremy Hoffman explains:

Read Quote of Jeremy Hoffman's answer to Pornography: What does "-4^(1/4)" mean and why is it connected to porn? on Quora

Instead, the porn links appear, and they will for other contradictions like " "15 30" -15." Interestingly (and luckily), Google doesn't seem to be returning porn results for any contradictory query, but only does it with search terms that include numbers. Somehow, Google's search engine thinks that these porn sites are the most relevant results for any numerical reductio ad absurdum. As for why these pages appear instead of something more innocuous, that's less clear. The most obvious answer would be spammy SEO. These sites may not have targeted this specific bug, but by casting a wide net of links across the internet, they appear to be benefiting from it. Solving the immediate problem of not returning results for impossible searches will be much easier than fixing the SEO spam issue — but Google will need to tackle both.

Thanks JC!