The advantage of internet technology has made it possible to appear a good number of websites to expedite social relations among people around the world. These are known as social network services. Facebook is the most popular. Other networking services are Google, Twitter, LinkedIn, etc. Social network services are web-based. They are giving ways for users to interact through the internet. The services have made it possible to connect people sharing their interests and activities throughout the world. People all over the world feel that they live together in a global village. Social network services are expanding fast for some reasons. They are less costly. The users can make personal profiles and upgrade their profiles. They can upload pictures, multimedia contents and modify profiles. They are allowed to post blog entries. The can take privacy protection measures too.