Joe Corneli gave a demo of GravPad at WikiSym 2010 in Gdansk, Poland. GravPad uses the Firefox Greasemonkey extension to attach an Etherpad to every page on the web. This mashup of web-plus-Etherpad, together with a “real-time recent changes page”, facilitates the discovery of interesting content and conversations. If you have Greasemonkey installed, you can…