Well, according to some sources, it is more popular than porn among 18-24 year olds. http://www.time.com/time/business/article/0,8599,1678586,00.html
While there is some skepticism of this research result and the methods used...it is true that Facebook is enormously popular, has eclipsed email even, for most of this age group. For many, this is not news (yes, I realize I'm about a year late with this headline).
The question is what does Facebook offer? Facebook is thought of as a social networking tool, and it does this quite well - - I personally love the status update feature because, rather than sending/receiving an email from/to one person, it goes to all of my "friends" at once. I get a daily glimpse into someone's life that might be near, across the country or across the oceans...
But, daily glimpses aren't enough. Facebook is not a substitute for face-to-face community. I want more than a glimpse into someone's life. I want to be able to sit and sip coffee or tea, or share a meal at table together. I want to 'see' them when they talk about challanges and be seen.
Facebook is a tool that helps us stay connected when life is busy and schedules are not easily put aside, and miles are not easily traversed, but I believe we are created to be relational people. And, I believe our community and world is served when there is face-time for sustaining and building relationships.
And, when Facebook or blogs, etc...are used in ministry as outreach, then we need to talk about how great God is and what God has done for the world, and continues to do in effort to restore creation to wholeness, to bring health and healing to all made in the image of the divine. May it be so, may it be so.