And that's the right place to use it to get people involved. Better than "7 people like your comment", "John and Mary endorsed you", ... This is really one of

And that's the right place to use it to get people involved. Better than "7 people like your comment", "John and Mary endorsed you", ... This is really one of a few examples of "hooking" people for good. There is even a book "Hooked: How to Build Habit-Forming Products" about it: http://www.amazon.com/Hooked-How-Build-Habit-Forming-Products-ebook/dp/B00HJ4A43S http://www.amazon.com/Hooked-How-Build-Habit-Forming-Product...