A&Y Dave in MD
I agree with Dave Parker that groups.io is superior for most functions. What I have found Facebook useful for is developing sources outside rail-oriented people for historical photos and information. I have a web site on the A&Y (since the '90s) and an groups.io email list dedicated to the A&Y to document and share. I resisted using FB for the purpose due to all the reasons cited. I shared some of my research in the io list, but got very little feedback. And most of the questions asked on the list from railfans had answers that have existed on my web site since the early 2000's. There was some appreciation, but not much energy.
However, on FB I found a few individuals were interested in the towns served by the railroad. I joined a few of those FB groups and saw some interesting info. So I bit the bullet and created a FB group dedicated to the A&Y. And wow! I got a LOT of interest from town historians and those into specific industries (I knew about those collectors of the petroleum industry, but who knew people were obsessed on brick kilns and other industries?). I have developed a number of new sources of info, received quite a few new historical photos (I model 1934, so it's hard to find anyone alive but relatives to interview these days). I got confirmation of some ideas and theories I had about photos of steam era freight cars that may or may not have been on the A&Y. I even got a photo of the switcher, confirmation of switching operations, and more info on a photo of the only apparent revenue freight car ever lettered for the A&Y. Turns out it was likely MoW, but it still came from the steam era (though too late for 1934). Still I now have a steam era A&Y box car to model!
So for those interested in getting the data they need to model freight cars accurately, FB is one more tool--with all the positive and negative aspects any one tool has.
When researching and building data on the steam era, I'm willing to take advantage of every tool available.
Just because groups.io doesn't have explicit data harvesting reputation, I would still wonder what is the financial model that makes this service available? I don't think there is ever a free lunch. As always, whether buying a "rare" "historic" photo or using a "free" resource to help with your steam freight car modeling needs, caveat emptor.
David Bott, modeling the A&Y in '34