The document discusses different types of social media including social networking services, blogs, and social bookmarking. Social networking services allow people to connect with others who share interests online, but also raise privacy concerns about personal information sharing. Blogs allow individuals to share thoughts and ideas with others, and the most popular blogs can receive tens of millions of views. Social bookmarking services allow users to organize and share bookmarks of useful web pages with metadata tags so others can discover resources on topics of interest.