Brian Stelter, writing for CNN: Why won't Facebook show the public the propagandistic ads that a so-called Russian troll farm bought last year to target American voters? That lack of transparency is troubling to many observers. "Show us the ads Zuck!" Silicon Valley entrepreneur Jason Calacanis wrote on Twitter when The Washington Post reported on the surreptitious ad buys on Wednesday. Calacanis said Facebook was "profiting off fake news," echoing a widely held criticism of the social network. It was only the latest example of Facebook's credibility problem. For a business based on the concept of friendship, it's proving to be a hard company to trust. On the business side, Facebook's metrics for advertisers have been error-prone, to say the least. Analysts and reporters have repeatedly uncovered evidence of faulty data and measurement mistakes. Facebook's opaqueness has also engendered mistrust in the political arena. Conservative activists have accused the company of censoring right-wing voices and stories. Liberal activists have raised alarms about its exploitation of personal information to target ads. And the news business is worried about the spread of bogus stories and hoaxes on the site. Some critics have even taken to calling Facebook a "surveillance company," seeking to reframe the business the social network is in -- not networking but ad targeting based on monitoring of users. Over at The Verge, Casey Newton documents inconsistencies in Facebook's public remarks over its role in the outcome of the presidential election last year. Newton says Facebook's shifting Russian ads stories and unwillingness to disclose information citing laws (which seem to imply otherwise) are damaging its credibility.