The easiest way to understand social networking is to think of it like high school. You had friends in school, and you knew quite a few people even if you weren't friends with all of them, but it's likely that you didn't know everyone.
If you ever moved to a new school -- or if you can imagine moving to a new school -- you start out with no friends. After attending classes, you start meeting people, and as you meet them, you begin associating with those that have similar interests.
Getting started with social networking is much the same as starting at a new school. At first, you don't have any friends. But as you join groups, you begin to meet people, and you build a friends list of those with similar interests.
Social Networking Architecture
Social networking is based on a certain structure that allow people to both express their individuality and meet people with similar interests. This structure includes having profiles, friends, blog posts, widgets, and usually something unique to that particular social networking website -- such as the ability to 'poke' people on Facebook or high-five someone on Hi5.
Profile. This is where you tell the world about yourself. Profiles contain basic information, like where you live and how old you are, and personality questions, like who's your favorite actor and what's your favorite book. Social networks dedicated to a special theme like music or movies might ask questions related to that theme.
Friends. Friends are trusted members of the site that are allowed to post comments on your profile or send you private messages. You can also keep tabs on how your friends are using social networking, such as when they post a new picture or update their profile. Friends are the heart and soul of social networking. It should be noted that not all social networks refer to them as 'friends' -- LinkedIn refers to them as 'connections -- but all social networks have a way to designate members as trusted.
Groups. Most social networks use groups to help you find people with similar interests or engage in discussions on certain topics. A group can be anything from "Johnson High Class of '98" to "People Who Like Books" to "Doors Fans". They are both a way to connect with like-minded people and a way to identify your interests. Sometimes, groups are called by other names, such as the 'networks' on Facebook.
Discussions. A primary focus of groups is to create interaction between users in the form of discussions. Most social networking websites support discussion boards for the groups, and many also allow members of the group to post pictures, music, video clips, and other tidbits related to the group.
Blogs. Another feature of some social networks is the ability to create your own blog entries. While not as feature-rich as blog hosts like Wordpress or Blogger, blogging through a social network is perfect for keeping people informed on what you are up to.
Widgets. A popular way of letting your personality shine through is by gracing your social networking profile with web widgets. Many social networks allow a variety of widgets, and you can usually find interesting widgets located on widget galleries.
Why Start Social Networking?
Social Networking is a nice form of entertainment, great for meeting people with similar interests, and can be a very effective business technique for entrepreneurs, writers, actors, musicians or artists.
Most of us have hobbies, or things that we are keenly interested in such as books, television, video games or movies. Social networks allow us to reach out to others that have the same interests.
For example, if you like movies, Flixster can help you decide if you might like a new movie just out at the theaters. If you like music, Last.FM can help you find new artists that are similar to your favorite bands.
Source: http://webtrends.about.com/od/socialnetworking/a/social-network.htm