Facebook Rules and Regulations?

I thought facebook was a great place to connect with people about diapers/sales/giveaways and promotions and now...OH BOY!  It has become a bit of confusion for me.  Okay, thats a lie cause I am so lost on what we can and cannot do!  So, I have a blog which is good because I can offer giveaways here - check - but, how do people ask me questions that want immediate answers?  No promotions or advertising through facebook?  Not entirely as you can pay facebook to run an ad for you.  (Here we thought facebook was a free display place - NOT)  That was my today rant!  LOL!  I am left with the question, is it worth having a fan facebook page?