You can no longer use Google Adwords to advertise things on Facebook. If you have anything that is related to Facebook and want to promote it, you will first need to get it approved by the Adwords team.
I learned about this from a friend who has founded a social media marketing company who was trying to do some advertising. He sent me a transcript of the phone conversation he just had with a Google Adwords representative so I could share it here.
Caller: Hello, I am calling because I received a promotion to advertise our company on Adwords.
Google Adwords Rep: Hello, let me just get your name, email address, and website please.
Caller: ____, _____, and _____.
Google Adwords Rep: What is it that your company does?
Caller: We assist small businesses establish an effective presence on Facebook and Twitter.
Google Adwords Rep: Alright well I will actually have to check with my higher up to get this approved because we recently stopped running Adwords for Facebook.
Caller: You did? Why?
Google Adwords Rep: Yes, well we are currently in a fierce legal battle with Facebook so we have started screening our Adwords. We are turning down adwords that promote Facebook. I will email you within the next two days to let you know whether or not your Adwords campaign is approved.
Maybe that fierce legal battle, which they are not discussing the details of, is related to Facebook’s advertisements, or the new Google Plus One service, which looks very similar to Facebook. I welcome comments about this.