Earlier quoted context omitted.
> You can't simultaneously have an invite system and a huge marketing push. What huge marketing push? All Google did was post a blog about it and send out some invites.
I never signed up for +1, yet I saw +1 buttons next to all my search results. While not a TV or radio ad blitz, that is a form of marketing.
+1 is a social recommendation and bookmarking service integrated into 3rd party websites and Google's search. It is orthogonal to Google+ (although both Google+ and +1 use the same social graph).