When are you friends with somebody at work ? and when are you just friendly? Sometimes it’s hard to tell. And when it comes to office friendships, how much do you have to watch what you say or do with your colleagues, both face-to-face and online? We try to figure out the rules of mixing friends and family with work by talking with Kate Dailey, who writes The Human Condition blog for Newsweek, and Tina Wells, CEO of Buzz Marketing, who has employed a number of her siblings over the years.