FB has several advantages.

- it's much easier to use images or videos to say what you mean
- you can select your audience
- you can avoid hearing from people you want to ignore
- you can use several different methods for notifying people about events
- you can find lots of people with similar interests or complementary expertise.

Downside is that messages easily drop out of sight much too fast. Mudcat is superb at long term memory.

Mudcat could usefully be complemented by an image/video store and diary system of the sort FB has. In practice when I've tried to use Mudcat's FB page that way, I got hostile responses from people who couldn't be arsed looking at the thread I was illustrating and got a diary-like post (intended to be of only short-term relevance) sabotaged by a power-crazed mod who didn't see the point of me doing it that way and couldn't be arsed consulting me.   So I'm not on Mudcat FB any more.