emblem-man posted...
Isn't the obvious answer just that they want to grow a mailing list for future events
I'd imagine it's this, plus just the basic social psychology of finding confidence in numbers. Knowing that a bunch of people are committed makes it easier for otherwise uncertain/nervous people to feel comfortable joining. Prior to my first 50501 event, I was hesitant due to fear of repercussions, but it was seeing the number of people RSVP'ing that eventually gave me the push I needed to join.