No, it is not a plug-in that just blacks out all political news. Developed by a University of Washington researcher, Balancer is a plug-in for the Chrome web browser that can tell you what your political bias is, based on the news you read, and suggest news items of an opposite slant. The idea is to get people who rely on specific Internet news outlets to look to other sources with opposing viewpoints, and thereby balance the information you consume.
Years ago, the research had a political blog but one day he realized that the only people reading it already agreed with them. The purpose of the blog was to start dialogues that would educate himself about politics, but as every visitor was of the same mind, these dialogues never happened, so he shut the blog down. He may not have learned about politics but he did learn about how people tend to go to news sources that reinforce their own biases, instead of seeking out more diverse information. Even without using it to find opposing viewpoints, the plug-in can still tell you where your bias lies, which some people may not be aware of.
Behind Balancer are the results of previous studies and existing media-bias indices, which it uses to place items on a spectrum from far left to far right. It also tries to learn about new websites by studying the biases of the people who most often visit them, if they use the plug-in.