Google+: 400 Million Registrations, 100 Million Monthly Active Users

"To begin with, as experienced by others here, my Google+ is extremely quiet."

There is an interesting thing about G+ which hasn't "seeped in" to a lot of users, is that 'share with my circles' doesn't share with people who are following you but you don't have in your circles. To hit those people you need to share to 'public' (and yes there should be a share to followers which is less broad than public but that is only my opinion)

Consequently you don't get as much 'fire hose' effect as you do on say twitter. And the APIs that post to Google+ are still not available as far as I can tell (pls correct if this is mistaken!) and a lot of my Facebook feed is not real news so much as auto-generated stuff from other apps. My point being that 'seeing it as quiet' isn't a good measure of anything.

Then looking at searches is another poor proxy because once you've figured out what G+ is, why search for it? And Google includes your G+ stuff in your search results (much to the dismay of many).

I suspect the better proxy is going to find referrals from links in a G+ post. How many links are sharing, how many links are being followed, how much traffic does it drive. That will be a better measure of its success I expect.

Edit: Taking a closer look at the trends link you provided, the bulk of the traffic relating to Google Plus occurred in the first 3 months of it being announced, after which traffic has remained fairly constant. This suggests that the initial peak was an initial surge of people searching for "Google Plus" to try and find out more about it.

It's easy to try and gleam meaning from the search data, but you need to be careful in the interpretation. On the other hand, it's curious to note that "Facebook" has maintained an order of magnitude higher search traffic than "Google Plus", despite Facebook being globally well-known.

But isn't that an advertised feature of google+? That you could 'friend' people, but then toss them in a [siberia] circle to keep their noise from cluttering up your feed? And similarly keep posts about your drinking vacation from being 'blabbed' to all your professional contacts?

It seems entirely possible that swaths of the social graph may have cut themselves off by pruning their circles down to the point that they were sharing to people who weren't listening to them and listening to people who weren't sharing with them.

Consider: When that co-worker from three jobs ago asks "does anyone ever use google+?" Would you really say "dude, I'm on there all the time. I've just got you in [siberia]"? It seems to me that most people would downplay whether/how often they use it.

That said, I'm on the US East Coast, so I could easily have a biased viewpoint. Perhaps all the Google+ users are elsewhere in the world? Or perhaps the little Google+ notification bar at the top-right of the default Gmail interface counts as an impression for the purposes of this study?

The new killer feature for me is the events. This weekend it was my friend's wedding and I made an event and invited my friends that were on G+, during the event your phone can optionally go into "party mode" which shares photos and video taken to the event page when the event ends your phone automatically stops sharing. Between the 8 or so that "attended" the event we gathered over 200 photos and a few videos, it was great. Showing people that feature convinced a few more to give G+ another, or first, shot.

Edit: just tried it. After creating a gmail accoun in mobile firefox, I had to click through an interstitial ad page punting the Plus app, and then find the hidden Cancel button on a G+ sign up form that was prefilled, and then I got to my new mailbox.

So, it doesn't ever publish private data without consent, but the UX is definitively evil in pretending to hold your mail hostage.

I switched to Android, and so did everybody in my office, yet nobody feels compelled to use Google Plus.