You’d be surprised at how many businesses are fond of censoring free speech in their workplaces. Following last year’s banning of the 2oceansvibe site in Virgin Active gyms, a recent study completed by OpenDNS has uncovered the ten most blacklisted websites by businesses around the world. You may or may not be surprised by the list.

With social media sites leading the pack, employers clearly believe that social networking is eating into workplace productivity.

How does this list compare with what you’d imagine?  Are these sites the biggest time-sinks? What’s your biggest time-sink?

1. Facebook.com

2. MySpace.com

3. Youtube.com

4. Doubleclick.net

5. Twitter.com

6. Ad.yieldmanager.com

7. Redtube.com [NSFW]

8. Limewire.com

9. Pornhub.com [NSFW]

10. Playboy.com [NSFW]

[Source: Geek]