I think it will stay free. Google relies on advertisements to make money. These ads are very much personalised. If they can scan your emails, they know even more about you, and can boast even more succes with their advertisements. Nobody else on the entire internet will be able to target people with ads as well as google can. The result is that google will have a monopoly on ads. And monopolies are where the money is at.
Incidentially, I think Gmail is about to go public, because I've also been bombed with new invites. 5 new ones 4 days ago, 5 new ones today... I'm almost out of friends here
