Here is some April data that estimates the video online market share (how many people visit each site). I didn't include every video site, but the ones that are top of mind for me.

1. YouTube 54.87%
2. eBaums World 15.22%
3. Google Video Search 12.53%
4. Break.com 8.57%
5. Bolt 5.47%
6. StupidVideos.com 1.67%
7. ZippyVideos.com 0.87%
8. Dailymotion.com 0.33%
9. Vimeo 0.18%
10. vSocial.com 0.17%
11. Revver 0.09%
12. Video.google.com 0.02%
13. blinkx.tv 0.01%
14. Cubebreak.com 0.01%