Historically no one's ever really used the Groups feature of this site (which can be found here:
Groups - Tesla Motors Club - Enthusiasts & Owners Forum).
I spent some time evaluating Groups when I was trying to decide on regional forums.
The benefit of Groups is that they are member driven. Whoever makes creates a group owns it and kinda moderates it. They also have a nice compact format.
The down side is that there are very few moderator tools, even for admins. Basically there's only the option to delete and undelete. There is no moving of "messages" (the equivalent of posts) or merging of "discussions" (the equivalent of threads), nor is there any option to split discussions. So if a discussion goes off topic, it is permanently so unless you delete a lot of stuff. There are also a bunch of technical things that work in "forums" that don't work in "groups". Unfortunately, there is no native functionality to convert group discussions to forum threads or vice versa.
So I decided to set up regional forums and assign moderators as needed. The activity in some regional forums is still rather low, but that may change over time as membership grows. I guess we'll see how it works out.