Seems that Google is rolling out some additional features for Google+ today, and that the ‘limited field trial’-fase is over. As of today Google+ entered ‘open bèta’, so invitations to jump aboard are no longer required. Everybody can sign up! Woohoow!
Google’s anouncement: http://googleblog.blogspot.com/2011/09/google-92-93-94-95-96-97-98-99-100.html