Given their similarity and reliance on growing a network of supporters, it seems like this will be a winner-take-all market. In any case, competition is healthy so may the best app win, even if Causes is way out in front now.

Unfortunately I can say with near certainty that we won’t be matching the same wild growth of the few dozen applications that had early access to the Facebook Platform, Causes among them. The primary reason for the viral growth of these applications was the ability for people to send private messages to all of their friends at once inviting them to the service, which drove the applications exponentially. However, Facebook dramatically curtailed this just about a week ago and now only allows users to invite up to 10 friends a day to an application. (Most users on Facebook have several hundred friends.) This more or less eliminates the possibility of going viral based simply on mathematics. (Since only a small % of people invite their friends and a small % of those accept, you need numbers much larger than 10 invites to really go viral.) In fact, if you look at the few hundred applications submitted in the last week or so, only a handful have more than 10,000 users, showing the dramatic decline in growth.

Nonetheless, I think in the long run the inital explosive growth of users is going to be less relevant than it currently seems. Either way, I think it’s important for all of us – Change.org, Project Agape, and others – to keep our eyes on the real goal at hand: not just acquiring new users, but translating that into deep, long-term engagement in social issues and with organizations.