It took me over a year before I "got" twitter. Now it would be hard to see how I could replace it - tracking outages, ongoing event updates, what my friends are up to, revolutions in Egypt - Heck, our company's public feed is actually the best way for me to track what's happening at our company than our internal mailing lists.
Of course, it remains to be seen whether there's any money in it. Everyone I know uses AIM - but I don't know if AOL has ever been able to monetize that.
Regarding Color - I'll give it a bit of time, and see what I think after I go to an event with groups of friends, and see what happens when we (and others) are taking pictures.