You'll get knocked back if someone else has already used it.

We won't use it for any other purpose than promoting this site to you, and it won't be visible on the site to anyone else.

Don't use the one your bank sent you - we don't guarantee that high a level of security - make it at least 5 characters long, letters and numbers, but no spaces or punctuation. Oh, and REMEMBER it! OK, you're probably drunk at home after a late Friday night, so you don't have to remember it - as long as you get your email address right you'll be able to get a reminder.