Surely, when you get up, you have seen many times that in your inbox there is an email that arrived at three in the morning on a Tuesday, with an offer of headphones. It is likely that you have been thinking about buying some, and that the algorithm and the cookies of your browser have placed that ad so timely in your mail. You are even likely to open the mail and click on the offer.
What you may not know is that marketing emails like this are tracking you. During this brief interaction, the headphone company has collected a great deal of data about you. Among other things, that company knows the time you opened the email, as well as your IP address, which can be used to determine your location.
