Twitter

Twitter is an online social networking site in which many people create an account to 'follow' their friends or celebrities, many of who have an account. This website also allows people to tweet things to other people, simply by adding an @ in front of the other person's Twitter name.

This website is used by Justin Bieber quite frequently, as he has an account that has been verified, thus allowing people to know it is really him. He has a very wide fan base online, as he has over 20,000,000 followers to date, second only to Lady Gaga, which is quite a big accomplishment for Justin, as he has not been in the singing business for as long as her.