Yes. But I have no interest in talking to +90% of the people on Twitter and Facebook. The success of app.net won't depend on how many total users sign up over the services lifetime. It will depend more on how interesting the people who ultimately sign up are. A lot of it is perception, right now twitter is something of a worldwide telegraph broadcast service, you say something in 140 characters to as many people as humanly possible. You're trying to garner as many likes and followers as you can.
App.net can't compete as a broadcast service, they don't; and never will have the userbase to do so. I feel like they'll have to differentiate themselves in some other way to be successful.
If the conversations end up anything near as inane as twitter it's doomed.
I don't see how this is true. If my friends aren't on App.net, I'll still use Facebook. If the people who discuss the issues that I tend to tweet about aren't on App.net, I'll still use Twitter. What will I then gain by using App.net as well, especially since most App.net users will probably syndicate their posts to Twitter?