Out of curiosity, what is the benefit of a list of the most recent comments rather than the most recently updated discussions? Surely having it all out of context would just be a bit wacky?
@dom: I have one board here where people come to hang out and use it almost as a chat room. So it's nice to have a way to see what's currently going on in different threads.
on top of FLC's suggestion, in order to pull this off via search (if that's the way you're going) you would need to include some kind of format to piece together the comments format type back together, as the search displays via plain text regardless if it's markdown or html