MailTag for Gmail allows you to add what they call Mail Tags to your emails, which communicate with a server and send information back to you via your Google Chrome browser. This means you may track links, track opening, re-opening and more.

Find out if your receiver opened your email

MailTag for Gmail allows you to see if your receiver has opened your email, and it tracks all subsequent openings. The program generates reports on things such as how many emails you sent today, how many you sent that month, and how many of them were opened. Despite the seemingly powerful mechanics behind the extension, it has a very simple design and interface. The way it is laid out and the way it functions is similar to how apps used to look and function in 2012. It feels as if it is missing a few interfaces, buttons and options, but one can hardly complain when the extension and its functions are given away for free.

Best for people running email campaigns

If you are a little nervous about your recipient opening your emails, such as if your recipient keeps telling you that he or she is late with a project because he or she didn't receive your email, then you may check up on that person with the MailTag for Gmail extension. However, this extension is best suited for people who are running email campaigns and who wish to run tests to see how well certain email subject lines work, how many links within the emails are clicked, and how successful the email is at getting people to convert.