Let's be fair though.

1) It's still in preview.

2) It has been somewhat primed with members, but has yet to reach the tipping point where everyone wants to (or even can) try it out.

3) The feature set is almost certainly not what it will be when it goes public.

My take on the field test is that it focused on bringing out the features most wanted by the technical crowd, who are crucial early adopters (and people paying attention to Google). The service will be refined until it is deemed ready for public consumption.

Finally, as with every social network, who is using it is more important than what it can do. We'll see if the "right" people take to it and bring everyone else with them.