Facebook: Is it worth being on it?

I was looking over my Facebook site.  I wonder why I do.  I find it to be a waste of my time.  It's a great way to keep up with family and friends, but I have been trying to cut back my postings.  Sometimes posting on it is like writing my blog.  I see that a lot of people might read it, but I don't get many responses.  If I am already doing this everyday, what's the point of doing Facebook also.  The ads are killing me.  They keep showing things that I have no interest in.  For some reason, they think I am into sports, diets and weightlifting.  I wish I could pick the ads I want to see.  My ads would be movie related only.