Social networking sites are not really bad, they are all simply communicating tools. In fact, all aspects are in the rule that when used properly, they can be very useful. However, when used improperly, they can be very dangerous and potentially cause harm.
Trust is defined in (Mayer, Davis, and Schoorman, 1995) as “the willingness of a party to be vulnerable to the actions of another party based on the expectation that the other will perform a particular action important to the trustor, irrespective of the ability to monitor or control that other party”
When people join social networking sites, they begin by creating a profile, then make connections to existing friends as well as those they meet through the site. A profile is a list of identifying information. It can include your real name, or a pseudonym. It also can include photographs, birthday, hometown, religion, ethnicity, and personal interest. Members connect to others by sending a “friend” message, which must be accepted by the other party in order to establish a link. “Friending” another member gives them access to your profile, adds them to your social network, and vice versa.
When people join social networking sites, they begin by creating a profile, then make connections to existing friends as well as those they meet through the site. A profile is a list of identifying information. It can include your real name, or a pseudonym. It also can include photographs, birthday, hometown, religion, ethnicity, and personal interest. Members connect to others by sending a “friend” message, which must be accepted by the other party in order to establish a link. “Friending” another member gives them access to your profile, adds them to your social network, and vice versa.
Benefits:
1) Help youth find their personal identity
2) Create a sense of independence
For example: Youth gain a sense of independence from their parents through using these sites, and this independence is good! All aspects of parenting, parents need to be active participants in these parts of their lives as well.
3) Communicate with friends
For example: Shy people have a chance to reach out and make connections.
4) Gain a sense of belonging to a group
5) Develop critical thinking and argumentation skills
6) Find support from online peer groups
Dangers
1) Predators (lurking on the Web)
2) Burglars, Identity Thieves, Sexual Predators (Privacy)
3) Cyber-bullying (size, speed, and strength do not come into play on the Web, anyone can be a bully and anyone can be a victim of cyber-bullying)
4) Undesired Attention (Youth may also find that the pictures they put out on the Web, or the comments they posted brought them undesired attention, either positive or negative.)
Ref.:
In the 1990s people connected through online chat rooms and belonged to communities. From that came Instant Messaging, which allowed people to talk privately one-on-one by typing messages to each other over the Internet. Eventually people began to connect on the Internet by creating online profiles on sites like 
