Was it that GMs ads didn’t work or just that GM’s vehicles stink? Advertising bad products doesn’t tend to help the bottom line much. The big thing to use FB for is the likes, those are people actually ASKING to see your ads.
Like eh?
The are a large number of people on Facebook who love, just adore, hitting the like button on your ad. When you try to contact them to see if you can help them they report you as spam and you get banned from friending any new people for months at a time.
It is the single most hostile advertising environment that I have ever experienced. I have spent a lot of time in advertising (owner and employee) and I know what I am doing.