Facebook: $100 billion valuation? Really?

I am trying to figure out the real value of Facebook. I have a Facebook page. I use it very little. Yes it does have an initial connectivity value  to it but what about afterwards. It seems  the personal investment of time  in such a social media platform seems to be a diminishing return. There is also a significant lost of privacy due to the fact that Facebook owns your personal information and sells it.   After this initial public offering I was left wondering why would it have a $100 billion plus valuation. I was looking at their advertising  revenues per user, at one point it was $33 now it is $2. They currently have very low CPM(Cost per thousand impressions). General Motors recently announce that they were going to stop advertising on Facebook because it did not work for them. Of course they have close 900 million users that gives them tremendous latitude to create new business models and ways of bring in revenue. But I still can’t figure out the real value of Facebook for me moving forward. It feels like a global distraction while really important things are happening that could determine our destines. Please somebody explain this to me. Thanks