This will sound dramatic, but could it be because the US is the most important market for both advertising and political disinformation? Regarding advertising,

This will sound dramatic, but could it be because the US is the most important market for both advertising and political disinformation? Regarding advertising, for companies like Facebook, they may have billions of DAU but still derive the majority of their revenue from rich countries like the US. In 2020 the US and Canada were 45% of Facebook's revenue according to this random website I found: https://statstic.com/facebook-revenue-by-geography/ https://statstic.com/facebook-revenue-by-geography/ That's way more than the other regions in terms of $/user, so Facebook is a lot more incentivized to over-optimize for engagement based on US users. Depending on how much the algorithmic feed changes from country to country, it's possible that other countries experience less polarization simply because their culture is weighted less in training the feed's engagement optimization algorithms. Regarding disinformation and political destablization, most countries simply aren't relevant enough on the world stage to be worth investing money in targetting in this area. The US, China, Russia, UK, Germany, France, Japan, India are all probably relevant enough. China and Russia effectively don't use facebook and are the most obvious non-US-aligned bad actors. They would also get way more bang-for-their-buck targeting the US than other countries. Note, I don't think is as widespread of a problem as many people think it is, but I bring it up because it's relevant in the context of political polarisation since there is strong evidence that it has occurred at least in the 2016 election: https://www.theguardian.com/technology/2017/oct/30/facebook-russia-fake-accounts-126-million https://www.theguardian.com/technology/2017/oct/30/facebook-.... Actually, the two combined can be scary. If you can use outrage (great for engagement) to drive engagement in your content which is designed to politically destabilize the US, you can get a huge reach. This is effectively what you see a lot of the time in highly-engaged US content on facebook anyway: politically inclined outrage.