A few minutes ago, I'm just reading the news from the RSS feeder app called Feeder and then suddenly I got a notification from x from Linux handbook which I was seeing in the feeder app. How?
I'm gonna start by saying Twitter doesn't respect your privacy, this we all should know. However, I don't think this is what you think.
You're reading an RSS feed that Linux Handbook publishes to. They published something and likely published it elsewhere at the same (or similar) times. It shows up in your feed, and you're reading it. At the same time, their post on Twitter has propagated to the point where followers are being notified and the algorithm is sending notifications to people that might be interested in it. You get a notification from Twitter. Panik
It's just a coincidence, and being skeptical has rotted your brain. Sometimes shit do just be like that. Everyone in privacy oriented communities has had this happen at some point, and because of how we think we end up feeling like it's malicious.
They do. Some of the bigger apps have their own zero day exploits that they use to get into things. Facebook is typically the worst, primarily because they bypass the app stores and make deals directly with manufacturers to install system apps.
Incidentally, in Android phones, WhatsApp was the primary vector for the NSA's Pegasus toolkit. They would send a WhatsApp call, then with no response from the user gain full access to the phone. How did WhatsApp give them access to the phone, if WhatsApp itself didn't have access? With iPhones, Pegasus targeted iMessages, so it makes more sense that they'd find a way in there.
We have known for more than a decade now that training machine learning models on huge user data sets allows to predict a lot of things with decent accuracy.
Twitter has been gathering a lot of data on all of its user, it is expected them to be able to predict interests like (and much more) this if you use their service.
No need to spy on your smartphone beside what you submit willingly https://hbr.org/2012/09/use-big-data-to-predict-your-c