VerPoilu
When using a browser they can get your user agent (https://www.whatsmyua.info) They can also get some information about your device, like pixel resolution, screen size (https://www.whatismyscreenresolution.org), gpu (https://hardwaretester.com/gpu) etc…
All of those data combined make a fingerprint for your browser, that can be more or less unique.
I recommend having a look here for more information about how fingerprinting works and how to protect from it, and to see how “unique” your browser is (https://coveryourtracks.eff.org).
When using an app, it’s a whole lot more complicated to escape from it, but one step I can recommend, is to delete your phone advertisement id (https://www.eff.org/deeplinks/2022/05/how-disable-ad-id-tracking-ios-and-android-and-why-you-should-do-it-now).
That been said, from my own reddit gdpr export, it doesn’t look like reddit is doing any fingerprinting of that sort. I haven’t looked so close at it yet, however.
I use TrackerControl. It doesn’t block ads in browsers, however, so I use Firefox and ublock origin there.
Beehaw defederated with lemmy.world and sh.itjust.works because both of those instances allow(ed?) registering without email verification/captcha. They said it is bringing bots and spams. Haven’t seen this issue personally. I recommend being a member of an instance that still federates with both lemmy.world/sh.itjust.works and Beehaw.
I think you meant this one: https://m.youtube.com/watch?v=8JrqH2oOTK4
Some developers will publish their apps on github, you can download it, and use a different app to get the apk file from the app you get from the play store, and compare the hash of the file. If they’re identical then Google didn’t meddle with it. If they’re not, either Google did, or the developer releases a different version to Google Play.
Revanced
Yeah, because books, the web, and educated people have a liberal bias.