I worked on this a long time ago and knew of others working on the same idea. I didn't pursue it for financial gain because it seemed too sleazy.
If you're curious what kinds of information your browser gives to a remote server, creating a "test.php" file with the contents "<?php phpinfo(); ?>", and opening that page in a browser is a good start. There are some other ingenious (read: I didn't think them up) methods, but I don't want to help the spammers n' spies.
If you're curious what kinds of information your browser gives to a remote server, creating a "test.php" file with the contents "<?php phpinfo(); ?>", and opening that page in a browser is a good start. There are some other ingenious (read: I didn't think them up) methods, but I don't want to help the spammers n' spies.
These days, I use them in forensics.