Social Network: A social structure made of nodes that are generally individuals or organizations. A social network represents relationships and flows between people, groups, organizations, animals, computers or other information/knowledge processing entities.

Del.icio.us:  (www.delicious.com) a social bookmarking Web site that serves as a bookmarks manager for users, similar to a collection of favorite links. You can add bookmarks to your del.icio.us list, categorize the bookmarks, tag them and also share them with others.

Digg: (www.digg.com) a community-based Web site, where users submit content and rate that content by "Digging" what they see and like best. A submission that earns a larger number of Diggs, and therefore is more popular with users, is moved to the Digg homepage for the category of content it belongs in.

Facebook: The name of a social networking site (www.facebook.com) that connects people with friends and others who work, study and live around them. People use Facebook to keep in touch with friends, post photos, share links and exchange other information. Facebook users can see only the profiles of confirmed friends and the people in their networks.

Facebook Page: Pages that are created within the Facebook social networking site that are based around a real-life interest or group or to declare an affiliation or association with people and things.

Flickr:  An online photo management and sharing application which allows people to make their content available online.

LinkedIn:  (www.linkedin.com) an interconnected network of more than 36 million experienced professionals from around the world. The site can help you make better use of your professional network and help the people you trust in return.

MySpace: (www.myspace.com) a social networking website with an interactive, user-submitted network of friends, personal profiles, blogs, groups, photos, music, and videos for teenagers and adults internationally.

Twitter: (www.twitter.com) a free social messaging tool that lets people stay connected through brief text message updates up to 140 characters in length. Twitter is based on you answering the question "What are you doing?" You then post thoughts, observations, and goings-on in your day. Your update is posted on your Twitter profile page through SMS text messaging, the Twitter Web site, instant messaging, RSS, e-mail, or through other social applications and sites, such as Facebook.

Xanga: (www.xanga.com) is an Internet Web host that provides its users (community) with access to their own online diaries and journals (often called blogs).  Xanga services are most popular with youth and young adults.

You Tube:  (www.youtube.com) a popular free video-sharing Web site that lets registered users upload and share video clips online at the YouTube.com Web site. To view the videos you are not required to register.