The folks over at butterfat.net have developed this Google Maps mashup called the Email Routemap. As you might guess from the name, it provides a graphical representation of the physical route travelled by the emails you've received. Plug in the "received" portion of an email header into the field next to the map, and see the traceroute plotted out:
The mashup takes the IP information of the last 4 mail servers that handled the email and it plots the servers on the map using lat/long info for each particular box. The geodata is collected from and served by HostIP, so servers will only show up on the map if the owner has provided HostIP with lat/long info. As you can see in the example above, the first two locations aren't plotted, but my mail server and the mail server of the person who sent me the email (she uses Gmail) show up.
You don't get to see the routes of the actual fiber backbones used, but you get a "shortest distance between points A and B" route that gives you a rough idea of where your bits have been.
The result is a very geeky mashup. Play nice! No stalking!
[link via reddit]
