In recent months, Pakistan's interior minister, Chaudhry Nisar Ali Khan, has increased pressure on Facebook and Twitter to identify individuals suspected of blasphemy. On 7 July, Facebook's vice-president of public policy, Joel Kaplan, met with Khan to discuss the government's demand that Facebook either remove blasphemous content or be blocked in the country.

On Monday, Facebook confirmed that it had rejected Pakistan's demand that new accounts be linked to a mobile phone number – a provision that would make it easier for the government to identify account holders. Currently, opening a Facebook account in Pakistan requires only an email address, while mobile phone users must provide fingerprints to a national database.

That social media would become the means for a government crackdown on free speech is a bitter twist for platforms that claim to want to increase openness and the free flow of ideas.

The advent of social media once heralded an opening for religious debate in Pakistan. Platforms such as Facebook, WhatsApp and Viber allowed individuals in conservative, rural areas to engage in discussions that were once possible only for students and urban intellectuals, unconstrained by the conservative norms of their communities.

"Until recently, social media afforded a measure of privacy where you could discuss the hypocrisy of people whose behavior was loathsome but who wore the thick garb of piety," said Pervez Hoodbhoy, a prominent academic and activist.

"Now the state is saying that we will track you down wherever you are and however you might want to hide," Hoodbhoy added. "Pakistan is fast becoming a Saudi-style fascist religious state."

The problem with engaging in potentially illegal speech on social media, of course, is that online speech leaves evidence.