I read a post on Mashable regarding 4 Myths About Social Media and Business. These are things I tell my new clients often. Mashable explains it nicely in the article but I wanted to give a quick summary here:
Myth #1: Small Businesses Must be on Social Media
Not everyone should be using Social Media. Do the research first. If you see a place for you, create a strategy before jumping in.
Myth #2: Set It and Forget It
You need to interact for it to work.
Myth #3: Word of Mouth Presence Isn’t There
Just because you are not being talked about, doesn't mean you shouldn't be there.
Myth #4: Social Media is Only for Broadcasting Messages
You can broadcast messages and get some value, but the real value is with interaction.
I suggest you read the whole article on Mashable. It's advice I often offer and it's great having a resource like Mashable to back it up. And thankfully, they've written the post so I don't have to. :)