As the site gets better at targeting users with more - relevant ads, the more profitable it will be. (huffingtonpost.in)
Online wallets are very popular at the moment but it can be very risky, there are people targeting who target the users of these online wallets to plant malware on their computer. (cryptohead.io)
Where we've seen the most success is targeting users who like pages similar to ours. (blog.bufferapp.com)