Well, often times, browser choice is out of your control.
Anyway, my view is that this kind of attacks the problem from the wrong end. (Ideally people would have up to date software because it just happened for them.) I think telling people their software is deficient just hurts the cause because it makes them angry at the web and not the browser.
(PS: I've worked at places standardized on Ubuntu Dapper. Its so old that getting Firefox 2 was a hack, and forget about Firefox 3... so the other end is similar, though perhaps not as deleterious to webmasters.)
Anyway, my view is that this kind of attacks the problem from the wrong end. (Ideally people would have up to date software because it just happened for them.) I think telling people their software is deficient just hurts the cause because it makes them angry at the web and not the browser.
(PS: I've worked at places standardized on Ubuntu Dapper. Its so old that getting Firefox 2 was a hack, and forget about Firefox 3... so the other end is similar, though perhaps not as deleterious to webmasters.)