Your ISP, personal computer, smartphone, etc... All of your internet-connected devices are actively collecting enormous amounts of information about you at all times. They know what sites you visit, what you type into search engines, which emails and text messages you send and receive, who are your friends and relatives from your contact list, what are you whereabouts from the phone GPS, what photos you have store in your galery, etc... They can listen in to your calls and even tap into your phone's camera, PC webcam and microphones on a whim. This much is public knowledge and people like Snowden went through great pain to try and warn us about it.

And this isn't just the government doing it either, even private companies are in on the spying. There is a shocking experiment you can do yourself: While your phone is connected to the internet, leave it on a table and pretend that you are having a conversation with someone else on the room and mention that you want to buy a certain type of product or service, for example: "Oh man this old TV sucks, I'm going to buy a a new one with a big flat screen tomorrow.". You absolutely will be shown a targeted ad related to the product you mentioned within two days.

There is a very interesting channel on Youtube detailing all of the different ways in which our devices are being used to violate our privacy and what we can do to mitigate and avoid some of this spying. I strongly recommend you check it out if you are interested in the subject:

https://www.youtube.com/@robbraxmantech/videos