[eth]

I'm not sure that a "Facebook Killer" will emerge in the near future. Remember that Facebook has somewhere around 600 million members.

While they may not kill Facebook or even amass half as many members in the next two years, I would definitely say that I can see Tumblr and Lockerz experiencing explosive growth over the next 12-18 months. This growth is significant because it is all targeted at the 13-25 crowd - one of the most lucrative and influential demographics.

So, Facebook is huge and still growing (albeit mostly in the 35+ age group) but the young crowd is spending time in places where they can consume (media, interaction, discovery) all in one place rather than broadcast (status updates, chats, messages).