Twitter

• Twitter is a mini-blog of sorts, allowing users to post short updates of 140 characters or less called tweets. Its short comment limit allows it to adopt an instant message type of interface, while giving it the public access of a blog. First launched in 2006, Twitter boasts significant popularity and progressively attracts more users as of April 2011. It even has a few celebrities along for the ride, allowing them to connect to their fanbases safely and easily. A user can set up Twitter to work with his cellphone, allowing him to send SMS messages as Twitter updates.
  
  

MySpace

• A social networking site that has enjoyed a strong following, MySpace allows a user to post her favorite music and specially design the look of her profile page. Users can connect with other friends on MySpace and even link a Facebook account with their MySpace page. Booming in popularity by late 2006, MySpace also became one of the first to highlight the many dangers of social networking sites. Later on, it had relinquished some of its former user base to other social networking sites, but remains a common name in the social networking world.
  
  

Facebook

• One of the most popular social networking sites in existence as of April 2011, Facebook originated as a website for college students only. As time passed, it became more inclusive, until anyone could create an account. Facebook allows a user to post pictures, connect with friends, create short "status updates" and create a family tree on his profile. He can share links, play online games and even connect with favorite businesses, television shows, celebrities.
  
  

Common Trends of Safety

• The popular social networking sites all share various trends in common, with safety foremost among them. Once someone posts something online, it's often disseminated so fast that she never has the opportunity to remove it completely. This goes for words, pictures and other sensitive information she may not want circulated widely. Social networking sites also potentially open the door for predators to spy for victims, for criminals to shop for easy targets and can provide old acquaintances with grudges with personal information to cause harm. A person should always exercise common sense when using a social networking site and never reveal personally sensitive information.