I'd definitely give it a look. Not really the same thing as running a business, but you know me, always buying pre-80's Ford parts. Where I used to search the forums, where demand kept prices high because everyone wanted the same thing, I'm spending a grand a month now on FB purchases on NOS parts alone...regional pricing is different, and you find a lot more people that just want to get rid of stuff or cleaning out their grandfathers barn.. I admin a dozen Ford, offroad and ford engine pages with 5,000 to 25,000 members, hasn't done me wrong so far.
The side landscaping/power wash business page my brother and I have, only nets us about 20% of our business...but our plates were pretty full to begin with, it could be quite a bit more if we actually dedicated time to the page.
I personally spend way more time these days on the fb pages than I do the forums.