In a social bookmarking system, users categorize their resources by the use of user-defined keywords or tags. Other users with similar interests can search the links in the system by topic, category, or tags. The results of these searches are usually more useful to the user than those conducted using traditional search engines on the web. Click here to read the "del.icio.us" explanation of social bookmarking.
Social Media Marketing with Social Bookmarking is a slideshow introduction to social bookmarking by Lee Odden. It includes an overview of the major players and tools to add social bookmarks to web content. It is itself an example of the sharing made possible by the use of Web 2.0 social software.
Another example of "content sharing" is a video by Lee Lefever - "Social Bookmarking in Plain English":
Click on the "Bookmark" tool at the foot of the right hand column of this blog to find a list of social bookmarking sites. Using this tool, you can bookmark this CEDICT blog easily in many or all of the social bookmarking sites at once. You may wish to use the following tags: e-learning, development, open educational resources, OER, open access, open source, Web 2.0, blogs, wikis, social bookmarking, social software.
More on social bookmarking.