In one word - YES. Here's a reason why - my sister went missing Thanksgiving Day. We found her 2 days later, but it wasn't until we'd started tracking her Facebook posts leading up to before the holiday that we'd discovered she was going to "hang out" with a "friend" for a few days. (Turns out that "friend" was a registered sex offender who was violating parole, and was living with a family member within 500 ft. of a park - something that's a clear no-no in the state of California).

Without having my sister's whereabouts on Facebook, we wouldn't have been able to track her or contact any of her friends that she'd friended to find out where she was. When someone's missing and they use Facebook, it's a great way to get a bunch of people looking all at the same time, or at the very least try to contact people that they know...

Say what you might about having "the older generation" on Facebook, but it can be a good thing if your parents are friended...