The Firefox RefControl add-on is a very nice little improvement to web browsing privacy. Why should a web server care what page I was last at? I think the reason is most often marketing, and thus the obvious preference is to not send referral information at all. RefControl allows one to do (or not do, that is) exactly that. It also provides some other options, but the most important thing IMHO is that one doesn't tell web sites exactly what Google search one came from, etc.
What web page are you coming from? This will tell you what one server thinks.
To install the add-on click tools, click add-ons, and then click get extensions.