Social Bookmarking is the act of publicly sharing, storing, and managing your bookmarks. (You can also keep your bookmarks private without sharing them!)
Through social bookmarking Web sites you can find other material on the Web similar to the sites you've added, promote your blog, and participate in a community of similarly-minded individuals. (Well, sometimes.)
In theory, a site or link that is well-received by the People of the Internet will be added to individuals' queue, which, in turn, will make the link or site more popular. As a result, more people will read the link or site because it will have a higher rating on the site.
Because the theme of Lessons for Old People is about blogging, I want to emphasize that these sites are great tools for bringing traffic to your blog. (Especially because your blog is full of high-quality content!) Even a low rating will bring traffic to your blog.
These sites are usually organized by topic—transportation, fashion, arts, humor, etc.—to help users sift through content. It's important that you have a clear understanding about what you've written, so you submit your content properly. These channels will also aid in driving more people you your brilliant blog.
Most of these sites also have toolbars you can add to your own browser, making submissions and exploring much easier. Moreover, most blogging software offer widgets and extras to allow reader to submit or like your content on their own.
We'll look at how to submit your posts to Reddit, Digg, Delicious, and StumbleUpon this week.
List of social bookmarking Web sites, Wikipedia
Technology Lesson: How to Back Up Your Bookmarks