The U.S. Supreme Court has yet to examine whether Facebook “likes” are protected as free speech. But in India, police arrested a 21-year-old woman last week for posting a “provocative” message to Facebook, then detained her friend for merely liking the post.

Shaheen Dhada’s post inflamed Muslim-Hindu tensions in the small west Indian city of Palghar, the AP reports. Dhada, a Muslim medical student, criticized Mumbai’s decision to essentially shut down much of the city as mourners gathered for the funeral of Bal Thackeray, a controversial right-wing politician. "Every day thousands of people die, but still the world moves on,” she wrote. “Respect is earned, given, and definitely not forced. Today, Mumbai shuts down out of fear, not out of respect."

Within minutes, a rowdy mob gathered around the block at her uncle’s orthopedic hospital and police took Dhada into custody, forcing her to apologize in a written statement. According to the AP, 21-year-old Rinu Shrinivasan was also detained for inciting “religious enmity,” or liking Dhada’s post.

While the Hindu reports that both women have since been released without charges, the case calls attention to the unpleasant risks of social media in some parts of the world. Users have credited Facebook and Twitter with launching revolutions, forcing political transparency and freeing information – but they also provide an easy form of surveillance for any government looking to shut down free speech. The Indian government has at times stifled online speech in an apparent effort to prevent the sort of sectarian tensions that have at times led to real violence in the country.

It's not just in India. In China on Monday, courts sentenced a 23-year-old model to nine months in prison after she posted, to the Twitter-like service Weibo, racy photos of herself dressed as a policewoman. (The official, though unconvincing, charge was “police impersonation.”) In July, an Iranian man was arrested after his college-age son joined a Facebook page that ridiculed a Shiite imam.

Social media surveillance is hardly limited to Asia, of course: During the 2011 riots in the U.K., the Daily Mail reported that several young women were arrested for posting “invitations to riot,” like “who’s up for it?,” on Facebook. More recently, a federal grand jury indicted four California residents, two of them U.S. citizens, on charges of joining al-Qaeda and planning a terrorist attack. According to an except from the indictment posted on Techdirt, the evidence against them includes a series of Facebook likes, posts and comments.

As The Post’s Vivek Wadhwa rightly points out, though, law often lags far behind technology — and both in the United States and abroad, the law is still deciding what constitutes free speech online. Dhada’s case is widely considered a test of India’s new Information Technology Act, which prohibits speech causing “annoyance” or “inconvenience,” among other things. (Online speech is, of course, annoying and inconvenient a great deal of the time.) In the United States, courts are only beginning to consider issues such as whether employees can be fired for liking something on Facebook.

For Dhada, however, those changes won’t come soon enough. According to the Hindu, she has deleted her Facebook account and fled Palghar with her family.

“First Pondicherry businessman, now 21 year old mumbai girl Shaheen Dhada and her friend Rinu Shrinivasan,” reads a Facebook fan page that has risen in her defense. “Next: all of us... Social media being hijacked by the powerful and the fundamentalists ... raise your voice now!”