Google+ has been around for nearly a month now, still locked down under invite-only mode. Traffic has decreased slightly, but it's not time to spell out the end of the site just yet.
Last week, Experian Hitwise found that Google+ received more than 1.8 million total visits during the week ending July 16, 2011. Approximately 38.37 percent of visits that week came from users aged 25 to 34, and at least 57% of all users were male.
Here's the update for Google+ traffic for the week ending July 23, 2011:
Note that this data does not include mobile or third-party application traffic, and it represents U.S. visitors only.
Sure, traffic has decreased slightly and the average time spent on the site has diminished by a matter of seconds. There are a few reasons that can easily answer for that. The biggest one is that most Google+ users are likely more familiar with the site now, and that initial allure and mystery is gone for anyone who has already received an invite. Thus, of course users are not going to check as often and for as long.
Once Google+ goes full on public, then we can expect numbers to seriously jump.