California Attorney General Kamala Harris found a modern way to take enforcement action recently: via Twitter.

Harris took to Twitter to compliment United Airlines on the company’s new mobile app, calling it “fabulous.”

She then took the opportunity to remind the airline about the requirements of the California Online Privacy Protection Act, which mandates that a privacy policy be posted on commercial Web sites where personal information is collected. “Where is your app’s #privacy policy?” she Tweeted, helpfully adding a link to the Act.

United responded that it would review the app to “ensure that our privacy policy is also easily accessible to United app users.”

Earlier this year Harris negotiated an agreement with Amazon, Apple, Google, Hewlett-Packard, Microsoft, and Research in Motion in which the mobile application platforms agreed to comply with the Act.

The companies – which represent over 95 percent of the mobile app market for smartphones, tablets and other mobile devices – further agreed to establish a format for consumers to report apps that do not comply with the law and to implement a process for reported noncompliance. Facebook joined the agreement in June.

Why it matters: Privacy has been a key focus of Harris’s time in office, and her public note to United Airlines should send companies running to check that their privacy policies are posted. “We have to both cheer the incredible advances in technology and at the same time protect consumer privacy. Attorney General Harris believes the only way to do both is through innovation in oversight,” a spokesperson for Harris told the Los Angeles Times. “She was proud to strengthen consumer privacy by requiring a privacy policy for all mobile apps, and expects every company to live up to their legal obligations of transparency and security.”