I'd agree that the Apple app store is a pretty close comparison. However, wonder how one would compare the value FB delivers for their 30% in fees to the value,

I'd agree that the Apple app store is a pretty close comparison. However, wonder how one would compare the value FB delivers for their 30% in fees to the value, say, ebay delivers to the auction sellers for the ~3-5% (guess) they charge in posting & paypal fees?