These tests are always interesting, and add fuel to the fire that the prominence of Google+ may be waning.
Of course, it does not mean the system, which is heavily integrated into so much of Google's system, is on it's way out. Perhaps only by name.
But now comes evidence that the company is indeed exploring a future where Google+ branding gradually fades into the background. Some developers implementing Google+ logins on their websites are now seeing an option to add a "sign in with Google" button, according to people who The Verge has spoken with. Screenshots show a simple blue button with a white Google "g" logo and the words "sign in" or "sign in with Google."Google Tests Sign-In Without Google+ [theverge.com]
The option appears to have been enabled for only a small number of developers, and for now is only visible to developers who are logged in through their developer accounts. Other Google users visiting web pages through their own browsers would still see a red button with the Google+ logo. The company confirmed the experiment to The Verge: "We are always testing things," a spokeswoman said.
It has always really bothered me that the login for AdSense or GWT logs you in to something you don't want or use. I have never been to the G+ site, but am frequently logged in there. It really kept me from having any urge to go there.