Traceability at a Glance is a free online tool which gives you a quick indication if you are easy or hard to trace.
IP address
The indication given is based on your IP address. When you are easy to trace, it is relative simple to determine your physical location.
Protect your privacy
As far as I know, the best way to protect your privacy is by following the guidelines given in the eBook Information Security for Journalists.
Traceability at a Glance is a spinoff of the ZOMDir project.