Firefox Add-on: RefControl

If you're paranoid about people collecting every single little piece of data from you, then you'll definitely need RefControl. The RefControl add-on extension for Firefox, basically allows you to spoof the referrer information on a site-by-site basis. This means that the sites that you designate not to know where you came from.

You can choose to send it based on site, or based on third-party requests which makes it a lot more functional than your regular referrer spoofer.