It's fairly common these days for companies to block staff access to Facebook, LinkedIn or Twitter. After all, you're supposed to be there to work, not peruse photos of your sister's cats. And so it should surprise no one that, as mentioned in this video by Lawrence Ragan Communications, social media lockdowns are used at more than half of today's companies.

It should also surprise no one that, despite being widespread, this tactic is a terrible employee relations move.

The Great Places To Work Institute (which picks the selections for its famous list, "The 100 Best Companies To Work For") notes that none of the 100 chosen companies does this. In fact, they actually encourage employees to use social media, even use it to help the company attract candidates to the organization.

It's a smart move — after all, if a particular corporate culture is good, there's little reason not to let staffers spread the word and champion the organization. Conversely, companies that block employee access to social media are simply showing their lack of trust in their people. And increasingly, potential job candidates — particularly younger workers who have grown up with social media — are sniffing this out and avoiding employers like this.

What about you? Does your company block access? Or if you discovered that a company you're interviewing with locks down social media, would it affect your decision to join them?