Phones listening to you and reading your mind

It can't read brainwaves as that requires dozens of electrodes glued to the skull and that only shows levels of various brainwaves - i.e asleep vs awake, rather than what someone is thinking.

Advertising s incredibly advanced and a lot of it is designed to appear almost invisible so when a person thinks about something they believe it a spontaneous thought rather than one that has been carefully engineered by subliminal advertising.

There's a great book on it here by one of the original inventors of subliminal advertising - Vance Packard - The Hidden Persuaders WARNING PDF

since then it's massively progressed by cutting edge science to exploit eye tracking and various other things.

The odd part is that despite it being a multi-billion dollar industry, there's very little evidence that suggets it is succesful in encouraging people to buy things as 99.9% of the time it's reactionary after the person has bought a product and they don't need another.