Usernames / Points / Notifications

Hello,

3 things:

1. Is there a way to make people have a uniqiue ID? That way even if someone changes their username you can still get to their page?
2. Can we have some more categories above Glorious?
3. Is there anyway to make a notification if someone says @username "Insert Comment." Maybe a pop-up on your page, etc.

If you want me to upload these all seperately, I can.

Thanks,

Zach