Though I have and use a facebook account, I do not use it for anything technical,
it is for silly stuff and friendly updates. I treat my facebook notifications accordingly.
I actually like the format of google group for these types of discussions, and am in several other similar groups(different topics).
from a feature perspective I also like google groups, I can control easily how I get the infromation only forum form or various types of emails,
I often will switch the way I access a group several times during it's lifetime, I can also easily categorize the mails from the groups in my inbox.
I have a clear preference to the current form.
Meir