Old browsers have plagued the evolution of the web and cost web designers and developers hours in backwards comptibility work. On top of that there’s the security threat. Anyway, if you run a website or a blog, you may want to join the Push up the web campaign.
“Pushup is an effort to push the web forward by helping users upgrade their outdated browsers. Give your users a better web experience and make life easier for developers out there by installing Pushup on your domain.”