No one is saying that the Facebook Initial Public Offering (IPO) is pure expectation but there’s enough scepticism out there to make the future of the IPO seem at least a little uncertain. General Motors decision to stop advertising on Facebook is being described as a wake-up call for the No. 1 social network. Do the people who use it really care about buying stuff off Facebook? Some media experts say they probably do but they have to be targeted better. There are billions of young users and even children buy things. Generally it seems too early to know if the site will take off as an advertising platform. One executive said there’s a lot of potential but it’s not a slam-dunk.