Been reading this thread with (sort of very mild) interest.
Leeroy, I've nothing against Facebook groups, I'm a member of a few but they seem to me to be very different from forums. They are just long lists of pictures and comments that behave more like a magazine to interact with. Something to casually browse through and see pictures and a few discussions that they elicit. But nothing like the forums that have search facility, different sections and are a great source of information and knowledge. Facebook groups just don't offer this ability IMO. But I still join groups when I like the look of them. I also don't think you get to know the people on them in the same way. Maybe it's because they are more picture based rather than reading what people actually think - there is less ability to get your personality across.
I did go to your site with a view to join but the header put me off because I got the distinct impression that it's a 1290 site and I am finding that 1290 pictures/gossip/news/issues doesn't interest me - it's one of the main detractors of this site too now for me - I have to scan all the titles and copy for the 1290 text and then don't bother reading it. The last thing I want to do is log onto a Facebook site and see a long list of photos of the same bike over and over again - Shiny orange and white with some rim tape and a sticker kit with a few different aftermarket silencers.
Good luck with your Facebook group though, it's good to see the numbers grow over time. I helped set one up a few months ago about bikes in the 80s and really enjoy being a moderator on that. Here's the link - my old bike mates are on the header with my old Kawasaki S3400 in the Lake district. We're up to 650 members now last time I looked, if it's a popular site then it will grow on its own.
https://www.facebook.com/groups/1628688430720757/