Cindy Cohn writes in EFF Deep Links:
Email being basically free isn't a bug. It's a feature that has driven the digital revolution. It allows groups to scale up from a dozen friends to a hundred people who love knitting to half-a-million concerned citizens without a major bankroll.Ironically this misses an important trend: email no longer drives communities; mailing lists are being replaced by blogs and feeds. Readers originate requests to blogs—so if micropayment system is introduced, everyone will pitch in, starting a microfundraiser.