My favorite use is keeping in touch with nieces and nephews (and their children, the next generation). I love seeing the photos of them since we are spread out over a large geographic area. Facebook helps to reduce that distance.
A family can also form a “closed group” which is open only to members. Such a group exists for one of my husband’s ancestral lines. It’s easy to send a message to all members with a request for specific information. I used this method to locate a marriage certificate and burial information.
(I think there are upcoming changes in the way these groups are handled on Facebook. The note says they will be “archived.” But then, change is the nature of the Internet.)
Genealogy societies are also finding Facebook helpful to highlight upcoming events, post updates on library acquisitions, and engage with their members. Of course, it’s possible to use a regular website to do this, but Facebook adds an easier interface by providing updates in a newsfeed. I don’t visit all my favorite genealogy websites each day just to see what is new. The Facebook newsfeed provides highlights to me.
And Facebook also serves a connection to this blog: a short summary of each blog entry is highlighted in my Facebook “status” updates. (Why that is called “status” isn’t clear to me.)
Not that many years ago connecting to the Internet meant using a phone line to dial into the Internet Service Provider (ISP). That seems primitive by today’s standards when we can check Facebook updates, email, and even renew a prescription through our smart phones.
The nature of Facebook will no doubt evolve … and I’m looking forward to utilizing it for my genealogy research.