This is a post I've made on my blog, but I'm posting it here also because I think you might find it interesting. This hack has been posted on a couple of other blogs, but I've adapted it so that it works with the contact form on your website. Basically when a customer submits a contact request through your site you can use this code to scan through their browser history and see which of your competitors they have also visited. http://www.marketinghacks.com/web-dev/check-your-competition-with-this-contact-form-hack-to-steal-browser-history/ It's interesting to know that this is possible, and if you want to stay safe you should clear your history regularly!
Hehee, pretty interesting (not sure how legal but anyway ) It's pretty fun, but I doubt there's much use for that... you should be aware of customer competition by other means than stealing somebody's browser history. Nice piece of script though.