Just tried registering a new GMail account and it’s still by invitation from my location. However if you’re based in Europe, the Middle East and Africa, Brazil, Australia, Russia and Japan, you’d be able to sign up a new account in a jiffy.
One of the reasons why GMail is by invitation only or uses SMS verification codes is to prevent abuse of the system especially for spamming. Now that Google is slowly opening the registration process to everyone, can we be assured we won’t get as many spam emails as before? Well, that’s one reason I dumped my very first email account on Hotmail years ago.