I turned the notification temporarily on to see how it works. You should get a notification now, if somebody has thanked you for a post. It's right there were your PMs are, at the top of the page in the "Welcome" bar where it says "notifications".

And you can always see in your profile which posts you thanked for.

I've also turned the stats on in the "userbit", right next to a posting. It says "Thanks (Given)" and "Thanks (Received)" there now. But I'm not really sure if we should keep that or if it's needed at all. Let me hear your opinions on this, please