When you open email messages in Mozilla Thunderbird, they may contain embedded HTML web content. Opening of this HTML content is same as opening a webpage in a web browser. This means that some of servers hosting this HTML content may track your online behavior. Fortunately, Mozilla Thunderbird allows you to enable the do-not-track feature which sends a request to all the servers not to track your online activity. Here is how you can enable do-not-track feature in Thunderbird:
- Open Thunderbird email client. Press the Alt key once to display the menubar in Thunderbird.
- Select Tools → Options from the menubar. This would open the Options window for Thunderbird.
- In the Options window, select the Security tab followed by the Web content section. Here you can check the checkbox labeled Tell websites I do not want to be tracked as shown in the picture below:
- Click on the OK button to save the setting. Now Thunderbird would send a request that you wish not to be tracked by different servers. However whether the request would be honored or not depends entirely on the tracking web servers.