I followed a link to the Workplace Area 51 proposal that contained my referrer code, and was greeted by this lovely notification:
Welcome to Stack Exchange Area 51!
Yannis Rizos thought you'd be interested in this proposed Q&A site. If you like the idea, you can click the "Commit" button below to be notified when the site is created.
Well, I know that already ;)
It would also make sense (?) that the notification doesn't appear when the visitor is already committed.
In other news, the Workplace proposal finally reached 100% commitment, yay!