Here's the juicy part. Kamkar's discovered ways to hide, and bring back, zombie cookies in eight different places on your PC. His program can reach from a website into your PC and deposit/retrieve persistent information in eight locations -- a veritable zombie cookie factory, to my way of thinking. If you venture to Kamkar's evercookie site, you can click a button that will plant a cookie in eight places. Go out to Windows, delete the cookie using whatever means suit your fancy, refresh the page, and shazam! The cookies all come back.
Samy's eight storage locations:
1. Regular, old, everyday cookie.
2. Flash cookie.
3. A very clever technique Kamkar talks about on his site that tricks PHP into remembering cookie information, disguising it as a custom PNG color palette. The technique uses an HTML5 "Canvas tag" to retrieve the information.
4. Another clever technique that uses your browser's Web History to encode cookie information. It's a variant of the CSS History Knocker method developed by Jeremiah Grossman.
5, 6, 7, and 8. All standard HTML5 storage locations, although No. 8 requires SQLite. (See my discussion of HTML5 in yesterday's Tech Watch article "IE9: Good enough to beat Firefox and Chrome?")
I couldn't get all of Kamkar's storage spots to work on all of the machines I tried; older browsers on older machines didn't cough up HTML5 locations, for example. But if you take your favorite machine to the evercookie site, I guarantee you'll be surprised and downright shocked.