From EFF:s latest initiative about browsers carrying identifying bits you can now test how many identifying bits your own browser has at Panopticlick. From this I got the idea for this online notepad.
If you already know the basics in http you can skip to the privacy pad part.
What your browser reveal about itself
For every page you visit, your browser must first download the page. This is done by sending a request to the server that usually looks like this:
GET / HTTP/1.1
Host: notes.endnode.se
User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.2pre) Gecko/20100130 Ubuntu/9.10 (karmic) Namoroka/3.6.2pre
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-us,en;q=0.7,sv;q=0.3
Accept-Encoding: gzip,deflate
Accept-Charset: UTF-8,*
Keep-Alive: 115
Connection: keep-alive
This is sent with every request for each html page, css-stylesheet and image that is requested. Especially the User-Agent line is mostly addressed since it is not only complex in contents but also that this varies a lot between different computers.
These headers can be combined into a fingerprint that the browser will reveal with every request.
Inverse Privacy Pad
The inverse privacy pad is an online notepad where you can write some notes and save them for later. Each visitor is presented a notepad based on their browsers fingerprint. This way every visitor will see a different text in their where their browser configuration differs.
Notes saved can only be accessed by others using the exact same configuration(or faking the same headers). Therefore the more unique your browser is, the easier you will be to track but you can be sure that there is a less chance for others to read you notes on this page.
Try it out yourself at the inverse privacy pad.
