Hi check out the OVMS Facebook gorup.
Before you do that, consider that Facebook is a company dedicated to making money from manipulating people and exploiting private user data with or without consent, which is led by a man of very questionable moral & ethics, and has a continuing history of bad political and social influence.
If you're ok with that, go ahead.
You are right in your clame, but fb already have the registered users data, and its an exelent and "free" platform to inform those people that there is free opensocrce projects that can improve the life of ther existring commercial products, if you do not like facebook you are probably better at googling things and found this homepage and this forum already, I think its it worth the presence at different platforms if we can reach a wider userbase and keep the project growing.
Likewise not everyone's life revolves around Facebook!
No FB here. I don't see a "need" for FB for this project either. People interested in this project can easily find it... well me thinks anyway.
My two cents :-)
The types of people who aren't able to use Google aren't really the target audience. If anything, I feel like it would clog up the forum with users who aren't able to read the manuals and generally don't know how to use the forums (i.e. posting a topic that has been covered numerous times).
Although maybe it isn't fair to be that exclusionary...