As improbable as it seems, you can run across a plethora of useful information while browsing facebook. For example, this mental floss guide to cemetery symbolism may give me worldbuilding ideas for one of the books I’m working on (Deathwalker). At the very least, it may serve as inspiration. How did I come across it? Someone shared it on facebook.
I don’t know about your fb friends, but most of mine don’t post personal thoughts and experiences nearly as often as they share interesting articles, videos, and images. Yes, they do the personal stuff, but they post 2nd hand stuff all the time (is this a general trend? I’m curious.).
Why not take advantage of all that information being tossed your way?
Now, I’m not suggesting this as your main research tool. As some of you have probably noticed already, there is a flaw to this sort of research, and that is the luck of the draw. Even though fb has a built-in search option that they are trying to encourage people to use for various topics, it’s hit or miss whether that will be useful for what you’re writing. It’d probably be most useful for characterization research since fb is nothing if not full of characters. And most of them are more than willing to put their behavior on display (which makes great book fodder).
For specific research (Victorian graveyards, for instance), you’re probably better off turning to Google or Wikipedia, especially if you need it quickly; however, keeping your eyes open couldn’t hurt. My friends post articles on plenty of topics that I would never think to look up, yet they wind up being strangely handy.
So why not keep the possibility in mind? You’re on there anyway, right?