Some more things about email address that need to be valid, not an invalid and non-existing one. Because later someone else can create that email address and steal your account.
theymos advised that it's better if you use email address like
yourUserName@invalid.bitcointalk.org
Make sure that your email address is secure. If you don't want to set an email address, use something like yourUserName@invalid.bitcointalk.org; don't use a random nonsense email like y@x.com, since somebody might create that domain/email.
This is something we recently started doing. If email sent to your email address bounces with an error message like, "This email address doesn't exist", then your email may eventually be changed to u...@bounces.invalid. (It's not possible for users to change their email address to something ending in .invalid, so this can only be an administrative change.) Because your old email didn't exist, somebody could've registered your non-existent email address and used that to steal your account.