That would be a fantastic feature! There a LOTS of times when I've wanted a way to bring specific people's (or groups) attention to a page or attachment, etc., and I've always had to resort to email (as they don't always see things listed in recent updates lists on busy sites / spaces).

Mixing CONF-3866 with CONF-5032 would lead to some pretty flexible and very useful features.

I'd like to vote for that, but I'd like to see it done in a much more robust manner, described in CONF-8629, because it would also allow me to do several things that I have wanted to do, for which the Metadata plugin is currently the closest thing to a solution, but still not close enough.

Briefly: instead of implementing yet another specific tag qualifier, why not just make the label system work with metadata tags? Ideally, the tags would be XML-namespace-qualifiable, but just generalizing what is already done with the my: prefix, and the for: prefix proposed here, would be a great start.

The social bookmarking plugin does something like this for the bookmark content. The main problem at the moment is the range of allowed characters for labels is less then the range of characters for user names, hence not all usernames can be represented as labels.