Social bookmarking is very much necessary for every website. It also helpful for getting huge traffic. Social bookmarking sites provide quality backlinks for website. It also helpful for indexing any page on google. So, social bookmarking have huge benefits.
Every website owner must do it perfectly for websites ranking. Here i share high pr and most popular top 40 free social bookmarking sites list. I think these links will help you.

Free Social Bookmarking Sites List

01. http://digg.com        7
02. http://reddit.com        8
03. http://folkd.com        6
04. http://www.mister-wong.com    6
05. http://diigo.com        7
06. http://scoop.it        7
07. http://linkagogo.com    4
08. http://oyax.com        3
09. http://sitejot.com        2
10. http://myhq.com        4
11. http://www.careep.org    4
12. http://www.activaging.org    4
13. http://startaid.com        2
14. http://designfloat.com    7
15. http://a1-webmarks.com    4
16. http://thinmarker.com    4
17. http://business-planet.net    2
18. http://newsgarbage.com    2
19. http://acymca.net        2
20. http://dizzed.com        1
21. http://klicknews.com    2
22. http://look-at-that.com    2
23. http://linksprocket.com    1
24. http://alplist.com        3
25. http://postolia.com        2
26. http://www.biolocator.org    3
27. http://diggita.it        5
28. http://blogospherenews.com    4
29. http://newsmeback.com    3
30. http://dekut.com        1
31. http://ikeepbookmarks.com    4
32. http://cloudytags.com    3
33. http://subbmitt.com        1
34. http://yemle.com        3
35. http://ipopu.com        1
36. http://openfaves.com    2
37. http://humsurfer.com    3
38. http://bildu.net        3
39. http://colivia.de        4
40. http://bookmax.net        4