The percentage breakdown for the top ten most blocked sites goes like this:
1. Facebook.com —14.2%
2. MySpace.com — 9.9%
3. YouTube.com — 8.1%
4. Doubleclick.net — 6.4%
5. Twitter.com — 2.3%
6. Ad.yieldmanager.com — 1.9%
7. Redtube.com —1.4%
8. Limewire.com — 1.3%
9. Pornhub.com —1.2%
10. Playboy.com — 1.2%