I just got another thank you, and it wasn't until now that I realized that this text:
I just wanted to let you know that I appreciated this post that you made. It's contributions like this that make this such a great community.
Is also not from the person, but from the system. It's kind of funny when you get that comment like that for posting, say, a limerick about a man from Nantucket.
I agree that the Thanks system is important -- one needs feedback.