Star Trek fans are familiar with the Borg - a civilization that traveled through space in the form of a big metal cube assimilating the collective knowledge of every civilization they encountered before they destroyed it. The knowledge absorbed by The Collective was instantly part of the brain of every member of the Borg civilization.
The 'people' of the Borg were humans fused with metal. Think Blue Tooth gone wild. When Borg individuals left The Collective, they separated from the knowledge base. When they returned to the cube, they reconnected with The Collective to 'rest' - assuming an even partially human being needs to rest - and to absorb the latest collective thinking.
Facebook may be an early iteration of the Borg civilization. When I connect, I am engaged in the stream-of-consciousness thinking of the world. I know about topics, issues, big and small that I likely would never have even known about otherwise. Since I work in my home instead of an office, the social network serves as my water cooler. My connection to the big brain of the world. When I disconnect, I feel vaguely uneasy. I'm missing out - or think I am. Facebook is a community and I need community.
Whenever anyone asks me about joining Facebook. I share the advantages. I also tell them what a huge time waster it can be. Each person makes an individual decision about whether to sign on or stay on, how much time to devote, what their 'presence' will be, how much they'll share. Just like any human engagement.
But it's worth remembering one thing about the Borg. The Borg's first comment to anyone they met was 'Resistance is futlile.'