I browsed a web site that deals with currency exchange rates. I did not register. I just browsed it. It is a one page site, no registration is required to access the information. I was surprised a few weeks later by a pop-up message at the lower right of my Windows 10, telling me about a significant price change.
It is cool already but I was wondering how did the developer know how to pop such a message on Windows while I am not at the site page? Of course, they captured my TCP/IP but how did they instruct my machine to do this? I assume it requires code to be installed on my machine and must get a message, maybe via timer, and a mechanism to pop up.
I have several firewalls, virus checker, ad-blocker, etc. installed!
From some of the comments and the answer I got, thanks to all, but I would really like to know how does the site do it? For example, do they store all ip values of visitors and go 1 by 1 to push the info to them? The site URL is: https://eldolar.live/