Sharepoint Portal Server 2003 is my first memory of an HTTP application (that sounds more appropriate than “Web application” 🙂 ) that allowed web content to be dragged and dropped around. Considering that SPS2003 only worked over IE, Google IG is definitely a good step ahead, at least in my books.
Then again, I came across this post on CodeProject and the guy was right – his site leaves you speachless! It just has to be seen, so head over there right now. Be warned though, it ran ok on IE7, but failed on both IE6 and Firefox.