Recently, I discovered that SwiftKey keyboard (I assume) was leaking tracking data from Incognito on Android. I would open an Incognito tab in Chrome, the keyboard would show up in "anonymous" mode, but products I searched for still turned into ads in Facebook/Instagram and AdSense in a couple of minutes.

I assume it was SwiftKey since it was the only piece of software that had access to those keywords besides Chrome itself (which I assume is not the leaker since it never leaked data from Incognito on desktop and because it also happened in Firefox Private Browsing). The "Am I Unique" fingerprint for an Incognito vs a regular tab is also different, so I assume it's not a matter of fingerprinting with server-side tracking.

We are being tracked by the least suspicious pieces of software nowadays, it's becoming more and more difficult to know where the actual tracking came from as we add more and more layers of complexity into our computers. It's scary to think about.