I think Google Wave will succeed...eventually. I'm not sure if they are aiming it as a replacement for GMail. Most non-technical people I talk to have no clue what Google Wave is and when I explain it to them, they usually could care less.
The concept is a big change from what we people are familiar with today and I think the only way for Google to try to make it a household name like GMail is to slowly merge the features into GMail. Once they get a large enough population raving about it, these people will usually make their friends/family/colleagues try it out, and from there adoption will gradually increase. But if Wave is not a replacement for GMail, I'm not sure people will go out of their way to use another service that most of the time their email program will do just fine.
Now, if you like the Google Wave concept, I ask you to give MooGroups (http://moogroups.com) a try. You get the power of centralized discussions directly in your inbox, without ever having to leave your inbox, without having to create an account, and while using any email program. Plus a polls gadget based on free-form text.
"Mailing lists 2.0" is an interesting term. It's kind of the principle we have used in building MooGroups http://moogroups.com. Instead of setting up a mailing list only for a specific group of people you email often, we make it so that essentially each group email is its own mailing list, so people who are part of that group email can email each other in an organized fashion or opt-out as needed.
Unlike Google Wave, MooGroups is available now, being improved upon everyday, doesn't require any signup, and allows you to use any email system.
Yes. That is the trickiest part of getting started. However that step negates the user from needing to signup with another service. Normally, you would have to signup with a service, create your list, then invite your users, then send your message. This simplifies all of that with the cost of 1 initial email.
I've thought about this a lot and there just isn't any other option. One way to get around this is to build my own web/iphone/etc client which would know exactly how to handle the Cc's. But that is out of the current scope.
Putting the recipients in the body is not really an option since there is no auto-completion for email address in the body.
I'm left with trying to hammer that concept into anyone that uses the service with clear/concise/clever instructions.
I was actually just going to use gmail screenshots, but I thought the Mac screenshots looked better. I tried to make it generic enough so that it could be just about any email program (minus the title bar buttons I guess).
Good Wave is definitely some exciting technology. I feel that MooGroups and Google Wave have some similar functionality but not a complete overlap. Perhaps even integrate with Google Wave in the future.