Determining what online content is trustworthy and what isn’t has become a key focus both for the platforms and for media companies. Facebook is now ranking news sources based on whether users (and its algorithm) see them as trustworthy, although many—including New York Times CEO Mark Thompson, who spoke at a recent event in Washington, DC—see that as problematic. Tesla founder Elon Musk has talked about a crowdsourced trust ranking system, which many see as equally problematic. Can something like trust even be quantified?

All of these questions and more come to mind with a new automated trust solution, an extension to Google’s Chrome browser that claims it will sort out who is a trustworthy source, and also plans to use blockchain technology to create a public, crowdsourced database of trusted sites. The plugin, called Trusted News, comes from eyeo, the German company behind AdBlock Plus, which claims to be the world’s most popular ad-blocking software. According to the plugin description:

TrustedNews is here to help you spot fake or suspicious news, and to recommend trustworthy sources instead. With so many sources of news available on the internet, how do you trust what you read? Fake news, bots and thinly-veiled opinion pieces dressed as news are everywhere. Trusting online news media is harder than it should be. We aim to help you cast a more critical eye over the news by rating for fake, questionable or trustworthy news.

The company says the plugin can distinguish between trustworthy and biased sites, and can also categorize satire and clickbait, which it defines as a site that “knowingly uses misleading headings or article titles to attract readers in an effort to increase traffic and revenue.” Of course, one could argue that lots of media outlets do this, including some mainstream ones. So how does eyeo’s plugin decide who is and who isn’t? By using a database that includes information from sites like Snopes.com and Politifact.

Eyeo’s database also uses an open-source list of untrustworthy sources originally created by Melissa Zimdars, a professor of communications at Merrimack College in Massachusetts. The list breaks down sites using tags, including “fake,” “satire,” “bias,” “conspiracy,” and “junk science.” The eyeo plugin also gives users a visual reference when they load a site—trustworthy comes with a green checkmark, satire a blue smiley face, biased an orange scale, and untrustworthy a red exclamation mark.

In the case of right-wing news site Breitbart News, clicking on the plugin loads a small popup card that says the site “contains politically biased content or promotes unproven or skewed views.” But will this dissuade anyone who has already decided that they like Breitbart, or are inclined to believe its reporting? Likely not. In fact, there’s some evidence that fact-checking by sites such as Snopes.com can actually convince true believers that the facts being debunked are true rather than false, a phenomenon known as the “boomerang effect.” It’s going to take more than a browser plugin to overcome that.

Sign up for CJR 's daily email

ICYMI: In Pittsburgh, an unprecedented blow to editorial cartoonist

Has America ever needed a media watchdog more than now? Help us by joining CJR today

Mathew Ingram is CJR’s chief digital writer. Previously, he was a senior writer with Fortune magazine. He has written about the intersection between media and technology since the earliest days of the commercial internet. His writing has been published in the Washington Post and the Financial Times as well as by Reuters and Bloomberg.