FirstClass was used in our school system, at least all the way up until I graduated in 2004. It was their central email/conference/announcement service. I am unfamiliar with the BBS part of it. I think I still have the Mac OS X, and the Mac System 7/8/9 clients somewhere, as we had to constantly install those on replacement systems, etc.. 

I assume SharePoint sort of takes over this in the corporate world.