How can one breathe the word "viral" and claim to debunk the concept without looking at data from one of the many Facebook apps that actually, you know, went vi

How can one breathe the word "viral" and claim to debunk the concept without looking at data from one of the many Facebook apps that actually, you know, went viral? [that's a rhetorical question, I fully realize that the answer is that they don't have any truly worthwhile data to look at] The lone Facebook app in the study is one that the authors made themselves, and it's no surprise if you've never heard of it: while I wouldn't take AppData's stats as golden, they're usually in the ballpark, and they claim Friend Sense maxed out at 317 MAU (http://www.appdata.com/apps/facebook/7890187783-friend-sense http://www.appdata.com/apps/facebook/7890187783-friend-sense) - to give you a sense of scale, the 2000th most popular app on Facebook had over 100,000 MAU (http://www.appdata.com/leaderboard/apps?fanbase=0&metric_select=mau&page=50 http://www.appdata.com/leaderboard/apps?fanbase=0&metric...). Even under the assumption that it's hard to get solid data on such low traffic apps, it's easy to conclude that no, Friend Sense is not a representative example of a successful Facebook application, let alone a viral hit... I can't give you numbers or anything, but I don't need to violate an NDA to tell you that if you're actually at a point where you're making real money off of Facebook apps, you're almost certainly seeing non-negligible virality, and you should be thinking about it, measuring it, and incorporating it into whatever business analysis you're doing. Your viral coefficient may not be greater than 1 (and if it is, God bless you and enjoy the ride, at least until you saturate!), but trying to increase it is nowhere near as futile as these authors claim - successful apps have network structures that can be very broad and very deep, and most would not have been successful at all without them.