Department of Justice, the company offered few details. A three-line non-explanation pointed the finger at "advertising by certain advertisers." Now The Wall Street Journal reports that the mysterious half-billion-dollar hit may stem from advertisements placed by "rogue online pharmacies" that break US laws. The DOJ investigation has focused on whether the search behemoth knowingly accepted ads from shady pharma sites, but it's unclear whether those sites sold counterfeit or expired drugs, failed to require doctor's prescriptions, or both. Obviously, if the company profited from illegal activity, it can be held liable -- a fact Google knows all too well after a 2007 settlement over ads for online gambling. The impending fine would rank among the highest paid to the US government; this news, by the way, did not come from Facebook.