If the least problem Facebook has is to make money, then why haven't they done it now? Don't you think it might be smart to get that little item checked off their list sooner rather than later?
If you wanted any indication to show how desperate FB are to monetize, consider their aggressive introduction of invasive (and I suspect redundant) ads over the last two months. There's no master plan there - the redundancy of "users first, monetize later philosophy" has seriously screwed up any plan they may once have had.
My advice to them: subscriptions, by the end of the year, before they start falting on their datacentre bills. People can't flock to a new free version of fb because nobody would fund it now.
Because to make money, people need to pay, and when people need to pay, growth slows. Their focus is on growth for the moment, and for that they need to spend.
It's like playing monopoly - at the beginning of the game you concentrate on buying as many properties as you can, because you know later they will bring you profits. If you immediately start building when you have just 3 cards, then you will earn money right at the start, but you will suffer later.
Facebook can sell itself at any time it wants to. Money is not the issue.
