I could, but to actually understand you have to try out, because it's an experienced quality and not some a thing that is amenable to description.

Before the corp FB instance we had Wikis, Email, Mailing Lists, Jabber and an internal "Youtube" like Video Store. It all sucked.

With the FB instance, the awareness of what goes on in other parts of the company is much higher, the noise level is lower, communication is more timely and generally you feel less stressed out. Email numbers are down, mailing lists practically do not exist any more (except for machine communication such as commit messages), things organize neatly in FB groups, and you kind of automatically find the groups that are relevant to work. The Wiki hardly sees discussion any more, and is mostly documentation.

There are a lot of problems in Workplace by Facebook, mostly in the messenger product (no spatial metaphor, i.e. no rooms, only groups, being the largest). But in general it has been an amazing improvement on what we had before.