eHarmony is under threat -- by that free service that doesnt even have to advertise: Facebook.  Just look at these mauling couples, made official by their status update.  Some of them are even bi-curious hook-up buddies ("It's complicated"), middle-of-the-night pokers, and stalkers...Facebook doesn't care.  "Thank God for Zuckerberg!"  A riff from a student variety show at USC, "Exposed," that takes on the double annoyances of eHarmony ads and Facebook love.