Remember when Google Plus traffic went up 1269% in one week? Well, you can scratch that. New traffic data from analytics firm Chitika show that the insurgent social network has erased those gains entirely.

Google Plus opened to the public on September 20, leading to the huge spike in interest that we reported, peaking around two days later. But just in the four days that followed, traffic sunk back down to where it was.

Chitika didn’t label the Y axis on its chart, but its “traffic index” shows the big peak over the same time period as the Experian Hitwise numbers we reported. The public launch generated tons of interest, but that interest wasn’t sustained for long.

We’ve put in a request to Chitika for more information about the study’s methodology, and we’ll update the post when we learn more.

In the meantime, we at RWW can informally corroborate Chitika’s findings that interest in Google Plus is on the wane. Our monthly referrals from there are down 38% since their peak, while Facebook referrals are up 67% and Twitter referrals up 51% over the same period.

As we reported last week, the +1 button isn’t gaining much traction, either. Despite all the new features and responsiveness to user feedback, Google Plus just doesn’t seem to be catching on. There’s only so much time in a day for social networking, and this newcomer isn’t converting many users.

We’ve reported some sneak previews of upcoming Google Plus features, like Google Voice integration and a Quora-like Q&A service. Maybe those will help Plus stand out.

Why aren’t you using Google Plus?