Google+ may have 90 million registered users, but they're not spending much time at the site.

We've been seeing and reporting statistics about this since last summer.

Anecdotally, it seems that Google+ is used a lot by Googlers, plus a few celebrities and bloggers, but not by normal people.

Now, ComScore seems to confirm it. According to ComScore's research, as reported by the Wall Street Journal, users with personal computers spent an average of 3 minutes per month on Google+ over the last six months.

That's compared with 7 hours a month on Facebook, almost 90 minutes on Tumblr, and 17 minutes on LinkedIn. Even MySpace users spend an average of 8 minutes a month.

Google would probably respond by saying that Google+ isn't a social network, so this isn't an apples to apples comparison. The point of Google+ is to gather information about Google users and their social connections in order to make other services, like Google Search, better.

Fine. But if nobody's spending very much time at Google+, then the information Google is gathering won't be very useful or accurate.