In an attempt to show us how much Google+ has grown, Google released numbers Thursday that prove little more than how few users it's gotten users to engage with the service's front end. At 500 million "upgraded" users, "Google+ is the fastest-growing network thingy ever," writes Vic Gundotra, the social network's senior vice president, on Google's official blog. And that might be true in some ways — Twitter's growth has slowed, as has Facebook's. But that title really depends on how we define "network thingy" and also "user." If that's a total of 500 million on Google+, and only 135 million of those are what Gundotra describes as "active in the stream," then only about 27 percent of people with Google+ accounts use it as a complete social network. The other 365 million, or 73 percent, are either people who plus-one things around the Internet, or have accounts because they also have Gmail and it's kind of all, uh, linked in and whatnot. In that case, Google+ is the fastest growing thing people sign up for to maybe share things, to maybe let it sit latent, or, for 27 percent of people, to interact with other Google+ users.