I just ran my first campaign in Facebook using the new experimental feature of targeting the ads towards maximizing clicks to my website (traffic driver).
I spent just 5€ and got an amazing 3600 clicks to my site for this amount! That's more than 7 click per eurocent! The cheapest click I have ever bought and if I am not wrong impossible to achive in Google adwords (I think 1 cent is the lowest bid there).
I am now running another campaign for 5€ to check if this pattern holds. If it does, that could mean a really serious threat to Google's business model (revenue from ads), as Facebook ads will be extremely cheap and at the same time excellently targeted.
Rather exciting new times!