If they don't give people invites soon Google+ will be DOA. People will stop caring before anyone gets a chance to use it.
This point is brought up often, but I thought it worth reiterating here. One of the biggest differences between GMail and Wave was that even though GMail ended up being released (very) slowly to the public, you could interact with other email users without them needing to get on to GMail.
Unfortunately the same is not true with their current offering of Google+. I wonder if there is anyway for them to balance "extensive testing, and careful releases" with "getting a quorum so that the early adopters find it useful". Perhaps allowing them to interact with Facebook so that they can still interact with their friends from Google+ without needing everyone on it (along the lines of GMail).
There's no way facebook would play along with that.
There is a way, but they need to do more groundwork. Facebook started University by University. Even if it's only people at my University that can use Facebook, that's OK, because I have something in common with those people. I don't need everyone else in my life to be able to use it in order for it to be of value to me.
They need to find groups of people who have something in common.
This could be University's, companies, sporting associations, etc. Anything where there is a group of people who have a reason to communicate with each other and where it can reach a critical mass of usefulness relatively quickly.
Of course, it will require a little more hand holding, but it will give the product a greater chance of success.
Use Buzz and Wave as examples.
I have absolutely no interest in interacting with my friends and family using those services. None. My Mum wouldn't even know where to start with them. They require too much effort. Besides she's got Facebook and everyone else she knows does too.
However, I would have happily given Buzz and Wave a go through my companies Google Apps account with the rest of the guys at my company. We try new services as a team all the time to see if we can find something that will help us in some way. BUT, these services were not available to me through my Google Apps account. Only through my Gmail account. Which is a bit of a PITA since -- at the time -- you could not be logged into both Google Apps and Gmail at the same time. So it was a non-starter.
My point? Facebook started small with University's. Students who had something in common. Google should probably start with businesses. Work colleagues who have something in common. Roll it out to one Google Apps account at a time. Hold their hand. Gain traction -- then with a solid base, spread your wings and jump.
It may not be the best approach but it would help bring people into the system with something in common.
(That is: select evangelists from the "keep me posted" list, invite them first, and let 'em do their work.)
I think it's much better for new users to come in slowly and find an already active service than for everyone to join at once, use it for a day and then leave.
But they should have at least one more level of private-mode before they go public. They need to make sure the early adopter community is tight first, kind of like Quora did. Imagine what would've happened if Quora went public from like day one. It would've basically killed the product. Or what if everyone knew about HN from day one? Facebook, too, was once only for college students. The early community needs to be very strong before it gets diluted by the masses.
The early adopters help shape the product before the "unwashed masses" join it, and I think they should give enough time to early adopters to get used to it, get to love it and have enough time to tell everyone how cool it is and how much they love it before they can actually invite everyone else and make it public.
You get one shot where each user will try your product, and decide to stick with it a while, or write it off.
If I get a Google+ account, if my friends aren't on it after a few days, then I think its crap because its got no content, and I go back to facebook. When my friend of now tries Google+, I'm not there to talk to; and the launch fails.
Its great to seed your product launch with influential early adopters. But these early adopters don't form a sufficiently dense social network to make the product worthwhile, on their own.
The adoption of a social product spreads like an epidemic. The frontier is either pushing out through the network, or its dying out.
I believe they should have stayed completely silent with Google+ until they were ready to throw it open to everyone.
A small company like Facebook was can launch a product in niche areas, and grow it out, building hype slowly.
Google cannot do that, because everyone knows who they are, and cares about what they do next - I think, for them, launching a network effect product (e.g. not gmail, as while e-mail depends on network effects, g-mail doesnt) has to be all or nothing.
They need to open it ASAP, to capitalise on the coverage they are now getting, and get dense enough social graphs for the service to persist.
I'm honestly not sure how you do successfully gain traction in something with this much level of (unavoidable) publicity. One thought I had was that something like video chat might attract people just to use that, and then perhaps organically discover other features that make them spend more time there.
I've seen it implied that no invites are planned until after the "field test", and who knows how long that period might be.