Twitter’s platform has contained software defects that leaked users’ location, and information about ads you may have clicked on (even if you requested that Twitter not share such data) to third-party ad partners, likely in violation of the EU GDPR.

Twitter also used information based on web tracking users all over the Internet (when user permission to do so was not granted).

This type of creepy ad targeting — based on so-called ‘inferences’ — is made possible because Twitter associates the devices you use (including mobile and browsers) when you’re logged in to its service with your Twitter account, and then receives information linked to these same device identifiers (IP addresses and potentially browser fingerprinting) back from its ad partners, likely gathered via tracking cookies (including Twitter’s own social plug-ins) which are larded all over the mainstream Internet for the purpose of tracking what you look at online.

Source: Twitter ‘fesses up to more adtech leaks

The use of “inferences” is very creepy as it results in Twitter making, frequently, false assumptions about each of us, sometimes even contradictory inferences. For example, Twitter has believed that I am both a Democrat and a Republican, even though I do not belong to any political party. This is according to the data dump I obtained from Twitter, which identified me as a political activist (far from it), left wing (no), and a registered Democrat, a registered Republican and a registered Libertarian!

In 2018, these inference dossiers were leaked on to the web – for millions of people. These dossiers contained inferred information on salary, wealth, political affiliation and hobbies.

In our highly politicized and violent public discourse, suppose this inferred data incorrect said your were a supporter of Trump or Antifa?

This information is also likely used by Twitter and Facebook to curate our news feeds. As you know, we do not see every post made by our friends or those we follow. Instead, each attempts to predict which posts would be of interest to us. A consequence of this de facto censorship is manipulation of our thoughts. By curating our news feeds (based on false inferences!), social media platforms are machine driven propaganda factories.