Most people receive dozens of emails each day without realizing they could be giving away personal information simply by clicking 'open.'
Email tracking software allows big companies, and even just the little guy, to send emails and not only find out when the recipient opened it, but their location as well.
Some call email tracking creepy while others, like job-seeker Bob Johnson, say it's a valuable tool.
"I know that my resume has gone where I sent it. I know how many times it's been opened, if an email has been opened 6 times I know there maybe some interest and maybe I'll get a call."
Google 'email tracking' and you'll see many companies offer the service for free or at a low cost.
Users simply put a provided code next to the recipient's email address to turn tracking on. Some services have senders select a box that gives an "email tracking" option. Senders can then find out if the email was opened, how long it was viewed, what links where clicked on, and what kind of device is being used, according to cyber security expert Dave Hatter.
Hatter claims tracking is legal in most cases but says it can be utilized for illegal activities such as cyber-stalking or harassing people.
"It's tracking what you did in there. So clicking those links will of course send that information back as well. So don't click the links if you don't want them to know," said Hatter. In addition to avoid clicking links, Hatter suggests opening emails in text-only mode.
"It disables all of this stuff. It'll block the ability for that client to make a request back to their server and consequently sent your information back," said Hatter.