Someone at barCamp asked me if there was anyway for a site developer to block greasemonkey scripts, and I said no. But after doing a little digging I came across this post from Dean Edwards, basically he is making it so the document.createElement method requires a password as an extra parameter. This will stop any greasemonkey scripts from being able to create dom elements to insert into pages, but it won't stop them from making changes to the existing dom. It will also mean updating any of your own code that uses createElement. Is there a war coming? Between people who want to hack about with the websites they're looking at and the site developers determined to control what you can see and do. If it comes to that I know what side I'll be on :)