Emailing is now a part of our everyday life, and many people are available through email almost 0/24. However, what most of us don't consider is the privacy of emails, as we perceive emails traveling as regular closed envelopes traveling to the recipient. However, in fact, if we don't use PGP or other encryptions tools, our emails can be easily surveilled on their way.
This motivated the creation of TracEmail, a Thunderbird Addon that helps understanding the problem. TracEmail analyzes the source code of the email and makes an estimation on the path the email possibly have taken. Then it puts this path on an interactive map, where the data surveillance regulation of each country can also be inspected. The tool is now available in Thunderbird Addons (at the moment it is under review), so if you are using a Mac or Windows, you can just give it a try. If you are a Linux user, you can contribute to the source to make it available on Linux.