I like it.
I agree that'd be a nice feature to have, as there are several users I'm having a hard time telling apart. Let's face it: when I encounter a fellow monk online, the name space is what has the greatest impact on my mental image of that monk. Of course, I may later on visit the home node but the handle is what I see first and that's what matters most. It'd be nice to have the ability to attach a small comment or reminder to a handle and have that comment displayed in the Other Users nodelet (I assume that's what you meant, and I also assume that the comment is only viewable by me).
Dunno if it's feasible, though. Or even desirable. The dev team might have more important stuff to deal with right now.
Cheers,
--Moodster