The bar is almost identical to the Meebo bar that adorned many websites at one point
Google acquired Meebo a few months ago and, despite having several popular products, some more popular with advertisers than with users, granted, most of its products have been shut down.The team was supposed to be integrated into the big Google family, specifically the Google+ side.
The results of that integration are beginning to show up as Google is now testing a Google+ bar, very similar to the Meebo bar that adorned many websites.
Google seems to be testing the new bar with some websites, one user noticed it on TV Guide. The bar is very similar to the Meebo one, except for being all about Google+ of course.
You get the Google +1 button and counter, as well as several site-specific links. The Google+ share box, the one found on most Google sites, is also there making it easy to share the page on Google+.
These options are already available via traditional buttons, but having them in a bar that is always shown will make them a lot more visible though, possibly, a lot more annoying.