Speaking of gamification, I have to be careful of the apps I download, as my kids have been known to "play games" on my iPad, and it turns out later that they were (inadvertently) shopping. ;)
But more seriously, we know that people like to spend money at places where they have fun experiences, and the social/online interactivity of the event you've described sounds like another layer of fun on top of the party itself. It would be interesting to know how many people didn't attend the event but heard about it through social media and later visited the hotel.
I started out just thinking about how this is a unique way of reaching a younger audience, but when I got to the end of the article and saw the 40% return rate, it really blew me away. I would love to be seeing a 40% return rate after a promotion. Wow.
The other cool thing about this type of promotion is that it can happen really quickly. Sometimes an event sneaks up on me, and I realize that I haven't done enough to get the word out. Seems like this app lets you make up for lost time with a flurry of posts within a short time frame.