How much money is Facebook getting from you?
On average in 2011, it generated $4.34 per user from advertising, according to its IPO roadshow. Depending on where you live it could be more or it could be less as you can see in this chart.
[If you are spending money on Facebook games, then it’s going to be more than what’s on this chart]
(Fonte: marketingcharts.com)
The chart that you see is what Google wants you to think is happening with Google+. It wants you to think the service is taking off.
The truth of the matter is that we just don’t know because Google won’t tell us.