"however, I don't get any when someone posts to my forum. Can I change that and I'm not aware of it?"
Below this message, there is a link. It says:
"Manage Email Notifications: Subscribe or Unsubscribe"
Click on it.
Every message, inside every forum, contains similar link.
"And is it possible to institute a way for an avatar to only be used by 1 person at a time?"
It us possible, but at this time we do allow more then one person to use the same avatar.
Cause, even if I would impose a rule that would prevent anyone from using avatar URL that is already used by someone else, anyone could easily download an existing avatar, rename it, upload it again to curezone, and then use it as their own.
So, no, if someone is determined to re-use the same avatar, he will easily find a way to cheat any system.