Social bookmarking has literally changed the way people aggregate and bookmark content. Gone are the days when you relied exclusively on bookmarking interesting sites you visit in your web browser's bookmarks menu. Now a days, the trend is to maintain all your bookmarks at a central location online and then share them with like minded people. Thus you have a process where by you never lose track of the interesting sites at the same time get to explore new sites which cater to your tastes but which has eluded your eyes.
One of the premier social bookmarking sites is del.icio.us which is a Yahoo venture. Here you can create an account and then start bookmarking your sites. What is more you can also tag your sites and enter short descriptions about it thus making it much more easier to manage.
Well if you didn't understand the concept behind del.icio.us by reading my short explanation, then I don't really blame you. A better bet would be to watch this Youtube video.
A word about the creators of this video
This video is shot by two enterprising individuals (couples actually) by name Sachi LeFever and Lee LeFever. They run a company called Common Craft and their job is to create educational (or promotional) videos such as the one shown above explaining various concepts related to technology and as you can see, they have done a pretty good job of it.
What I really find unique about the video is the way it is shot, where they explain things using pictures printed on paper with a little bit of animation thrown in and of course using neutral accent English thus bringing it down to the level of a child's understanding. You can also find many other videos on their site. And if you have some spare change, you might be interested in hiring them to do a similar video of your site too ;-).