Privacy is a big selling point for tech firms, particularly those that are asking to host your personal data. That's what's so potentially damaging about reports Thursday from The Washington Post and the Guardian that the U.S. government has broad access to data of nine leading Internet firms as part of a surveillance program known as PRISM.

(Flickr credit: Scott Beale) (Flickr credit: Scott Beale)

Apple, Google, Microsoft, Yahoo and Facebook have denied that they have granted the government access to their servers. But the fallout from the revelation of PRISM — regardless of whether the companies knew about the program — takes some of the shine off of these firms' reputations.

Users have reacted to the revelations with outrage. It's hard to capture all of the reactions out there, but let's just say words like "disgusting," "big brother" and "outrageous" are some of the most common phrases cropping up across the Web. Even those who expected to hear news like this someday seem disappointed.

In recent years, online companies have worked hard to bolster their reputations for privacy. Google releases quarterly transparency reports on government data requests. Microsoft — believed to be the first company to participate in PRISM — recently launched an entire ad campaign for their new products touting that "privacy is our priority." Consumers expect a certain amount of data privacy, and when companies fail in that aim, they hear about it in the form of lawsuits, boycotts and angry recriminations.

Details about how the program works and how much control the companies may have had are still coming out. But Twitter's conspicuous absence from the list of companies involved in the program hasearned it some goodwill from users reacting to the reports.

The company already had a good reputation for privacy, earning high marks in the Electronic Frontier Foundation's evaluation of which tech firms do the most to protect user data or at least let consumers know about government requests. The fact that Twitter's not implicated as being a part of this program further bolsters that credibility.

The social network has not commented on the reports about PRISM, though the company's chief technology officer Adam Messinger did say on the network that he's "proud to work" with Twitter general counsel Alex MacGillivray.

Along with that message, he included a link to an article citing this comment that MacGillivray made in the New York Times: "No one wants a pen that's going to rat them out."

And that gets to the heart of the outrage: Americans are with or near their smart phones for an average of 22 hours a day, according to a recent report from the analysis firm IDC. On a typical day, we spend about 32 minutes on Facebook. We contribute to approximately 3.3 billion daily global Google searches.

The volume of information has given consumers, particularly younger users, incentives for locking down their privacy settings and turning to services that place a premium on privacy, or at least the idea that every message you write won't end up in a permanent record somewhere.

Trust is the currency on which tech companies build their businesses. Undermine that, and you run the risk of upsetting the whole ecosystem.

(The Washington Post Co.'s chief executive and chairman, Don Graham, is a member of Facebook's board of directors.)