"Advertising" isn't that big of a secret. It seems like the default monetization strategy. If that is the strategy, it's all just in the tactics and targeting.<p>Ads aren't the most innovative way to make money, but it's not easy, either. Reddit, for example, still hasn't remotely figured it out despite huge potential and an enormous user base. FB and Twitter are getting there, but it's not been an easy road and investors are still expecting more.