[easp]

Huh? You seem to be implying that a growing user base gets them unreasonably high advertising rates. Are you suggesting that advertisers are willing to overpay for facebook ads because of their strong growth trends? That may have been the case when Microsoft did their deal, but that was a while ago. These days, advertisers either have past experience to draw on, or they can dip their toe first without making a big commitment. Either way, I expect most of the ad revenue on Facebook is from people paying what they consider to be a fair price.

As for virtual goods, this has been part of their revenue mix for quite a while too. From the whispers I heard a couple years ago, it wasn't the majority of revenue, but it was a healthy chunk.

Facebook's estimated average revenue per user has hovered at the same level for a few years and is something like 1/3rd what MySpace's ARPU was. Both suggest to me that Facebook has still been favoring growth over revenue, and that as growth starts to taper off, they'll have plenty of opportunity to offer a "free" service and make a profit at the same time.