What just happened? The mixing of controversial politics and social media is nothing new, but in this instance, the platform itself has taken a more active role in pushing a message. Users have discovered that Twitter is running ads from Chinese state media attacking the Hong Kong protesters.

The government-backed Xinhua news agency has been paying Twitter to promote its tweets, which say the protesters are "escalating violence" and calls for "order to be restored."

The protests began as opposition to a bill proposed by the Hong Kong government, which would have allowed the extradition of criminals incarcerated in Hong Kong to China. While the bill was suspended on June 15, pro-democracy demonstrations have continued.

Social bookmarking site Pinboard highlighted the ads, tweeting that Twitter is "taking money from Chinese propaganda outfits and running promoted ads against top Hong Kong protest hashtags."

The revelations put Twitter, which is one of many websites banned in mainland China, in a dilemma. Running the ads is going to look bad for the company in most people's eyes, but the platform could face a backlash from free-speech supporters if it is seen to be blocking ads from a major publication, even one that is considered a Chinese government mouthpiece.

Both Twitter and Facebook have been fighting Russian electoral interference and propaganda on their respective platforms for several years now, and while the ads aren't as subtle, it could open the site up to claims of hypocrisy, especially with it being paid to show them.