It 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, recently added, or belonging to a certain category like shopping, technology, politics, blogging, news, sports, etc.

You can even search through what people have bookmarked by typing in what you are looking for in the search tool. In fact, social bookmarking sites are being used as intelligent search engines.

Websites like Digg, Reddit and Propeller focus on social bookmarking of news-related items such as politics, sports, technology, etc. These websites will often feature breaking headlines and bloggers discussing the current news items.

Social news sites are different from standard social bookmarking sites by focusing on specific articles and blog posts rather than websites. Because of this, they can be a great source of news, and they also offer the ability to participate in the discussion by leaving comments on popular news items.

Social bookmarking and social news allow you to specifically target what you want to see. Instead of going into a search engine, typing something in, and then searching for that needle in a haystack, you can quickly narrow down the items to what you are looking for.

Because many social bookmarking sites display recently added lists and popular links, you can both stay current and see relevant information. For example, let's say you are interested in learning more about social shopping. You might search for social shopping on one of these sites and come up with two articles: one with a hundred votes and one with two votes.

It's pretty easy to tell that the article with a hundred votes might be your best choice. And this is a lot easier than putting "social shopping" into a search engine and seeing page after page after page of links that may or may not be useful.

So, what started out as a way to send bookmarks to friends has really grown into social search engines. You no longer need to page through thousands of results to find a needle in a haystack. Now, you can simply go to a social bookmarking site, choose the category or tag that matches your interest, and find the most popular websites.