Social Networks in everyday life

After reading Danah Boyd's article about social network sites, I found it interesting how she articulates the dependency of teenagers on these sites. The first quote, "If you're not on MySpace, you don't exist", sums it up. Before these social network sites existed, the means of communication among teenagers had become mobile phones either through calling or texting. This brought teenagers away from face-to-face relationships, however, the use of the social network sites have moved teenager communication even further away from any type of verbal or face-to-face relationship.
In addition, teenagers on these sites have the ability to portray themselves to the virtual world in any manner that they choose. In essence, teenagers can directly portray themselves in a profile for the virtual world, or create an entirely different person. If they create a completely new and imaginative person, it's essentially the same as a second virtual life. The basis for communication and a relationship with the majority of "friends" becomes dependent on their virtual world. Instead of responding to something said on a social network site in person or through the use of a phone, the entire dialogue is in the virtual world.
This makes me wonder where the end to this virtual dependency is? The dependency of social networking sites for teenagers is diminishing their ability to verbally communicate their thoughts without delay in everyday situations. So, is the dependency going to evolve into a different form of life? A second life?