Why do links have a circled number?
When I hover over the circled number, a text pops up saying "x clicks," but if the number is 2 or more and I click once, the link is opened.
So why does it say that?
off-topic: Also, why does Snap! automatically convert capital letters to lowercase? I'd like my username to be "GeoKid," not "geokid."
by x clicks it means that link has been clicked x times
It's just something to tell everyone how many times that link has been visited.
It's more or less standard practice among sites with logins that the username is case-independent but the password is case-sensitive. (That's why they feel the need to warn you about the case sensitivity of passwords before you enter yours, and warn you if you have caps lock on in your keyboard.)