I'm not overly certain if this is possible with the current forum software, but it's something that's proven handy on other forums.
Basically, the mention system allows for one user to tag another user in order to notify them or a direct response to a post (and/or being 'mentioned'). Functionally, it appears as @Isinfier, @WarriorFish, @sfPanzer, @Brother 'shopping at' Argos, whilst also hotlinking to that users profile. To the target of the 'mention', it appears as a notification informing them that they've been tagged.
It's a nifty, helpful little system that can make threads a little easier to work with.