From when you read the email to exactly where you read it, there are programs widely used that are spying on people who have no idea it is happening.
Reading an email is something most of us do so often we don't keep track of it. But some email senders are keeping track of your every move.
"It helps you track when someone has read an email, how long they looked at it, if they forwarded it on, where they were when they read it," lawyer Rania Mankarious said.
Mankarious speaks from experience. Before heading to Crime Stoppers, she was a lawyer and knew of cases where email senders tracked emails, including where the email was read.
"Lawyers use it, police use it. A lot of people use it all the time," she said.
Mankarious says the law allows tracking, but not access to content of the email. There are several websites that allow email senders to track messages.
In some cases, those who get the email can figure out if the message is being tracked by looking for links embedded in the email that the sender wants them to open or by downloading an image.
But some tracking services do not give any indication the emails are being tracked.
"As the reader, you have no idea what is happening. Your are just clicking away reading the email, forwarding on -- you have no notice, you have not agreed to it, you do not know," Mankarious said.
So it's up to email readers to be vigilant.
"There is nothing that is going to tell you that this is being tracked in any kind of way," said Alex Diaz with Top Tech Experts.
We reached out to some of the tracking companies but have not heard back. In the meantime, some tracking emails use images or links to get this information, so be cautious about clicking on things in an email if you are concerned about possible tracking.