I see MMO's relying on browsers, because the web model and the subscription model align nicely. We had browser based (probably still do) text based "MMO's" that

I see MMO's relying on browsers, because the web model and the subscription model align nicely. We had browser based (probably still do) text based "MMO's" that relied on the browser, and there's no reason that something like World of Warcraft or Second Life couldn't run in the browser fairly easily today.