Facebook is the world's biggest social media network and now has over 1 billion users! There is serious potential here to make great affiliate commissions.
Google+ is still one of the new kids on the block, but with the might of Google behind it we are sure that it will grow in dominance and importance.
If you aren't doing some kind of affiliate promotions on Pinterest then you are missing out! This photo sharing site gets monster levels of traffic, and if used correctly can earn you some easy affiliate sales.
If you are building a list (which you should be), then Twitter is a great way of increasing your reach and having another avenue to share your content through.
Video is the king of online marketing right now and YouTube is the king of all video sites. If you know what you are doing you can drive A LOT of traffic to your affiliate campaigns from YouTube.