Social bookmarking sites are a popular way to store, classify, share and search links. In a social bookmarking system, users store lists of Internet resources, which they find useful. These lists are both accessible to the public or a specific network, and other people with similar interests can view the links by category, tags, or even randomly. I've used almost all bookmarking widgets for my blog, but found some very useful and really working and finally compiled a list of 6 Best Social Bookmarking Widgets for Blogger Blogs I hope this helps you in finding the right one for your blog.
Add this was one of the oldest method to be used for social bookmark. After that there are many players come to this market. I think share this is also good and they have added few new features as well which you should try..