I think something that might be useful would be to parse the "@" symbol to automatically create links to user profiles when followed immediately by text in comments & forum threads.

Example:

I'd like to hear from @MedicineStorm about this as well.

In addition, users could be notified via email that they are mentioned in this manner. This would be especially useful in threads where that particular user has not participated.

Edit: One caveat might be usernames with whitespace. It would probably have to be mandatory for the writer to use dashes ("-") in place of whitespace, since that is what is used in such username URLs.

Example:

This is based on @Clint-Bellanger's work.

(Notice above that link parsing should end with special punctuation like periods (".") & apostrophes (" ' ").)