I want to "unfriend" a co-worker on Facebook. How can I do this to her without creating friction at work?

Unfriending someone on Facebook is technically easy, but socially difficult. Before you banish your co-worker to the electronic ether, consider the recent research from Purdue University social psychologist Kip Williams. His studies suggest rejection on social media hurts just as much as rejection in person, because many of us now calculate our self-worth by how many online friends we possess.

With that in mind, let me suggest an alternative approach that may wreak less havoc: Keep her on Facebook, but curtail what she can see. The site's privacy features allow you to customize what specific individuals can view on your page, from your political views to your status updates. This will keep your co-worker at arm's length without adding tension to the workplace by sending her to social-media Siberia.

But if you're still intent on unfriending her, it's best to just do it without offering an explanation - because an explanation may heighten any negative reaction by seeming patronizing. If she confronts you, simply say you want to keep your work and private lives as far apart as possible.

To avoid similar problems in the future, you might be wise to reserve Facebook for family and friends outside the office. With social media making it too easy to merge our work and private lives, keeping them separate is key to keeping your workplace sociable.