For teens facebook is the most fun distraction, they talk about that all the time with their friends. For me social networks are indispensable and I enjoy a lot this.
I asked ten friends why do they use social networks and 99% answered that they can comunicate all the time and get interesting and important information abuot everybody however they told me that with facebook or twitter is impossible get concentration and do homework it´s the principal reason to cancel this social networks.
So social networks today are very important and you can have more interaction but you have to separate the fun and obligations.