At some point after you open an account with Wikipedia you'll probably want to "fancify" your signature, make it more "unique". And Wiki allows for a lot of creativity on your part. Read about that at Customizing your signature.
Here's a tip! You might decide to put a space in your sig, perhaps between your Username link and your Talk-page link. Unless you want your sig to "break in two" at the end of a line, don't just hit the space-bar key, use one of Wiki's "non-breaking space" options. It's real easy, and that way all of your sig will completely wrap around to the next line. Now that's keeping your sig together!
Read more about it here: Non-breaking_space
and also here: Wikipedia:Line_break_handling