I believe they tried to get around this problem by giving each person 10 invites. Some people sold them, other people invited their friend or team which made it more useful.

Yeah, I was given 20 nominations, and decided to pass them to most of my team, then realized our team is way too big :)

I'm also a little surprised by the author's criticism of having no one logged on at the same time. In our limited application of it, the value is not exclusively in real time communication, but in a better organized (non-linear) communication timeline.