Social networking sites are one of the best means to promote traffic to your blog.But in order to obtain proper traffic,social networking needs to be used effectively.Most important is to ensure that the title of the blog that your are bookmarking is attractive enough.Additionally provide good descriptions for the blog.Titles and descriptions are one of the most important factors.Also there would be no point in just bookmarking your blog.You need to add more friends and join more groups and it is important to bookmark other people's content also.

One of the major advantages of using social networking is that it is free to use unlike advertising,
where money is involved.

Check this forum sitepoint.com/forums/showthread.php?t=632889 for further details.