Hey, just a suggestion here (I know it'd probably be pretty troublesome to implement!)
Have you ever seen a post and been amused by/liked it, but felt that a reply would be a little awkward or wouldn't say much? Or maybe someone else felt the same sentiments as you and replied earlier, so you think yours might sound redundant?
What about a "Like" button? Just like Facebook, or along the lines of Twitter's "Retweet". It would be quite cool. Just a fast, simple way for us to show that we like a particular reply.
You are water on a hot summer day
for a thirsty daughter, finding her way.
AFAIK, there's no code you can get to implement it on a ProBoards forum, either. Having run my own for five years (Just moved coz of the new ToS) I know there's a lot of things out there you can customise if you have the right codes, but I've never seen anything like that.