[bmr]

Groupon's real "dirty secret" is that they've brilliantly navigated the seedy world of affiliate marketing. As far as I know, Groupon uses the same affiliate networks as Acai scam artists (as opposed to say, building their own a la Amazon) and is (was?) willing to pay several dollars for a single email address.

How they managed that is the real secret and I would be extremely interested in that story.