"SMTP has outlived its usefulness" (was: Forwarding services)

I'm just saying that lots of people will not see the requirement of having to register as significant hindrance. When a large part of one's contacts use some service, one is inclined/pressures into using that same service; and once one is using that service, that threshold of having to register falls away.

I'm not saying that's a good thing. Either everyone uses the same service, which leads to a monopoly, which is not desirable. Or everyone uses different services, but when different people in your group of contacts use different services you're pressured into registering for several of them. Not good either.