I just started a facebook page for our lodge. There are about half a dozen of us, mostly the officers who are on there, but its not yet a major communication tool.
We are bringing in younger and more computer literate guys, so I expect it to take off.
I utilize facebook as an online trestleboard and am fairly happy with the results. It is definitely working as a contact point for people showing interest also.
My Lodge's FB is at:
Grand Lodge of California's FB is:
It's become great for our young members; many of them are on FB.
The older bro's... Not so much.
FB hasn't really been good for prospects; we get most of our prospects from referrals from the Grand Lodge website (http://www.freemason.org/becomeMember/index.htm). That being said, it's been great to share pics, etc.