Normally, I’m not a big fan of following the rules. I’ve always operated under the motto “it’s better to beg for forgiveness than ask for permission.”
However, in the rapidly changing wild west world of chaos known as Social Media it is probably a good idea to have a starting point.
The folks at Fast Company have produced a very good infographic that lists the 36 rules of Social Media. They might not all apply to your situation but they are a good starting point when you are defining your Social Media strategy.