User Stats?

I have a question more out of curiosity than anything else.  Using me as an example, when I make a forum post, under my picture it says, "Regular," followed by the number of forum posts, then a group of various color stars and location.  My question is how about "Regular" and the stars.  I see different people with nothing there, or various other terms - expert, veteran, extreme veteran, etc.  I also see various numbers of stars.  (See attached photo below with arrows pointing to specific area of question).

How are those terms determined?  How can you hide them if you so choose.  What is the significance of the stars? (I do know how to hide # of forum posts, that isn't my question).

Thanks in advance.  Like I said, just curious.

(user info.jpg)