This is the first example I've ever heard of where a browser-upgrade banner worked. Every time I've tried it on sites I've worked on, the "please upgrade" banner does nothing.

Years ago, we even tried turning it into an intrusive pop-up for a percentage of users. They just clicked through the pop-up, presumably without reading it.

I wonder if it worked in this case because it started a movement?

> Between YouTube, Google Docs, and several other Google properties posting IE6 banners, Google had given permission to every other site on the web to add their own. IE6 banners suddenly started appearing everywhere. Within one month, our YouTube IE6 user base was cut in half and over 10% of global IE6 traffic had dropped off while all other browsers increased in corresponding amounts. The results were better than our web development team had ever intended.