social bookmarking is tagging a website and saving it for later. Instead of saving them to your web browser, you are saving them to the web. And, because your bookmarks are online, you can easily share them with friends.
Not only can you save your favorite websites and send them to your friends, but you can also look at what other people have found interesting enough to tag. Most social bookmarking sites allow you to browse through the items based on most popular,