Social Bookmarking... this is an important phase of promoting a website. 

Social bookmarking means sharing the particular page. You can say Tagging one page with a Social Bookmarking website. For example, You can see SHARE option for every post or video in facebook. It helps you to share that particular content with your list of friends. Social Bookmarking sites do the same.Here, You are sharing the page or link. This increases the backlinks of your website. This increases Page rank.

Social Bookmarking is absolutely Free of cost. Following are the list of Bookmarking website all over the web. 

1. Digg 
2. Folkd 
3. Spurl
4. Kwoff 
5. LinkaGoGo 
6. SpotBack 
7. MyLinkVault 
8. A1 Webmarks 
9. Tagza 
10. Plime 
11. Searchles 
12. DoFollowDigg
13. Feedmarker 
14. Memfrag 
15. MySiteVote 
16. OldRec 
17. Wagg It 
18. Otherwhirled
19. OYAX 
20. TeDigo
21. MyPIP 
22. Yattle 
23. Kabulis
24. Bukmark 
25. Ciudadlaberinto 
26. Cool Search
27. Gozoof 
28. Tamilers 
29. Ziki
30. Agroots
31. Best of India
32. Promote Your Website Free 
33. Zobbed 
34. Dizzed 
35. Yomash News 
36. Bookmark 24 
37. 180 Blog Network
38. 180 Blog Network 
39. Yoo Submit