Bookmarking is a way of saving favourite websites. Social bookmarking is a way of saving favourite websites through a site that makes your choices available to share with other people.
By Bookmarking, you can have access to that stuff from anywhere in the world. It's similar to puting a site in the favaourite menu of your machine, the only difference is you don't save it on your machine but on a social bookmarking site.
Bookmarking is just saving your favorite sites in your PC.... So that you can check for the site later while Social Bookmarking is the way of interacting of sites from each other.. Through links....