The fallacy of social media is that it can turn a non-social personality into a well-connected socialite. Take a close look at the people who are able to leverage Twitter, LinkedIn, Facebook, etc and those who use these tools a LOT but never quite make the cut. I think what you'll find is that the social networking tools can have a multiplying effect for those with strong external networking skills, but are just a time sucking device for those who are not otherwise socially inclined.
Over the years that I've been on Facebook and Blogger, many have seen and ignored my Facebook posts and few have bothered to read my Blogger entries even when posted to Facebook. Why should they? For one thing, my interests are arcane and obscure. For another, other than occasional blowups they mostly are not excited tirades. To quote RB Fuller, the most special thing about me is that I'm an average, ordinary human being. I'm just not worth knowing. The sad truth is, the people we do pay attention to aren't really any more worth knowing either, it's just because of cosmetic factors or conceptions of affiliation which are largely unfounded.
But who really benefits from us socially inept types? As an experiment, I posted the salt phrase "A TREE FALLS IN THE FOREST" to my personal Facebook profile, and asked anyone who saw it to post the phrase to my wall. Over the following months, no one noticed. Over a year, one old friend noticed and took the bait. After that, no one else. So my profile is essentially unnoticed by 99% of my own network. Why bother filling it out? The only real beneficiary is Facebook itself, which is now valued in the billions. I'm certainly not against a company making money, but it was my time, my effort, and my demographic data that they are using to do it, and I'm not getting a material benefit from it.
My advice? Blog if you will. I do it for self therapy, not because I expect a following. I fully understand that I have been and probably always will be the proverbial tree falling in the forest. Don't invest your time and demographics in Facebook unless you can reasonably expect to get measurable, material results in exchange for your disclosures. Got someone to talk to already? Then go ahead and tweet, post, and text them. But don't make the mistake that these tools will substantially change the number of genuine friends you make. If people don't already naturally gravitate toward you in real life, real people won't gravitate to you on Facebook or Twitter either. You can chose to pretend (in which case you're selling your soul for a false sense of intimacy) or become embittered (in which case you're just ruining the experience for everyone else), but perhaps the best thing to do is to allow the kids to enjoy their promiscuous social networking and focus on more rewarding things in life.