While it's unfortunate this forum isn't running vBulletin, and even more unfortunate that a custom forum software is being developed (I can't see a reason why, when vBulletin will easily kick its ass like it kicks SMF ass), why not (while still using SMF) add this mod to the forum:
http://www.smfpacks.com/alertmod http://www.smfpacks.com/mentionsmod/This would make it possible to use
ChangeTip much like on Reddit, Twitter, Github, etc. I'm guessing the same could be done by using vBulletin's "mention/user tagging" mod.
If you decide not to, at least try to code a "mention system" in the new forum, so that ChangeTip could eventually be used on bitcointalk.org as well.