If you are not there, you really are not missing much yet — for now, it’s only populated with Google geeks, some hackers (missing many F/OSS developers though) and the cheerleader sycophant tech media panoply (Leo Laporte, Scoble, TechCrunch, the gruber-bot, etc.…). In all likelihood, it will not be that interesting until it is wide open to general public and even then, if enough adopt, which I have doubts about such success.
The “circles” feature is the big distinguishing feature apart from Facebook, but other design decisions are baffling to me (i.e., you would think it a no-brainer to share between Google Reader/gmail/Google Apps/etc., but the plumbing connections with that are bare and/or non-existent.
If you have a G+ account already, look me up — under “Naum” (I believe I am the only “Naum” there, if there is another, pick the pensive looking cat in the hockey helmet).
Also, I have some invites if anyone is interested — but act quickly (message me your email) as they seem snap the “invite window” shut too rapidly.
Invite window closed.