How about a "Who's online now" box listing users that are on now, and a way to message them? I know this is way out there and not the function of AB, but now that I've been coming to the site for a while I see answers from the same people, and wouldn't mind connecting with them.
It could also be done internally and therefore anonymously (using AB User Names rather than real e-mail addresses). However, it would be rather a big implementation for something which is essentially nothing to do with the type of site this intended to be.
Good idea (I'm adding a similar one next)- are you from funtrivia by any chance I wonder (if we could pick favourite threads we could get email notifications on all as well). I suspect the software has different options here though.