This will make it easier for Facebook users to bookmark their profiles. You can also find your friends easier.
Instead of having accessing someone this way:
Your profile address can look like this:
If you are a Facebook user, like many that I personally know, then grab your favorite name before it is gone.
Facebook will suggest some names based on your first name and last name. You can also pick something that is similar to your email, nickname, or other usernames you have used in the past.