"Mark Pilgrim, author of 'Greasemonkey Hacks: Tips & Tools for Remixing the Web with Firefox,' gave a talk Tuesday afternoon at O'Reilly's ETech Emerging Technology Conference in San Diego to show off the promise (and peril) of the Firefox Web browser add-on, which is nearly at its one-year anniversary.
"Greasemonkey is not a car mechanic, but a tool for manipulating and customizing the design of remote Web pages (without the knowledge of publishers) when sites are viewed through the popular open-source browser, Firefox..."