It's just intended to be a fun hack that works surprisingly well, not a serious solution to the problem of providing support for older browsers. Although come

It's just intended to be a fun hack that works surprisingly well, not a serious solution to the problem of providing support for older browsers. Although come to think of it, if all the rendering is being done on the server side, and nothing but an image map is being delivered to the older browser it should be perfectly safe for these ancient browsers to navigate to even the most dangerous websites, provided that the server side component doesn't get hacked, because the server side component will be delivering nothing but safe images.