Bookmarking is a system of organizing websites that you want to re-visit, but rather than bookmarking them in a folder on your computer, you bookmark them on a special social bookmarking website. If you do a Google search for "social bookmarking websites" you will find a list of the top social bookmarking sites that you can join to add your favorite sites to.
The way you go about this is to use keywords that represent your favorite site's content, or in other words, you "tag" it. You can then make your entries public or private. The ones that you make public can be seen by anyone who visits the social bookmarking sites and looks up the keywords you used to describe your bookmarked sites. The public display will also show who created the bookmark, when, and how popular those keywords are.
There are many advantages of using social bookmarking as opposed to simply bookmarking. By making your list of popular sites public, you have the ability to share information with others who are looking for the same type of information. They will be able to find a list of sites that display exactly what they want just by logging into a social bookmarking site and typing in some relevant keywords. This is a tremendous way of helping others find useful information, or sharing resources with a group of people.
Aside from the benefits of resource sharing, social bookmarking can help generate traffic to your site and blog. You can set up your blog to link to your favorite tagged sites, and allow your blog visitors to easily bookmark your site. This will result in more traffic, possibly a better Google Page Rank, and potentially more sales!