Why the circled number after links?

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.)

Okay, thanks, @slate_technologies