you are willing to anger 20% of your userbase? you can do whatever you want, just don't expect everyone to go along. but if i run a business and my revenue depends on my browser users, i'd be very hesitant at loosing even 5% of them, let alone 20%.
well, it depends on whether the site breaks if a browser feature is missing or not.
if it doesn't break then you have a graceful fallback which i did already suggest as an acceptable way to support new features in case they are not supported.
but if the site breaks in some way, it may prevent me to complete the objective on the site. if i wanted to buy something, and the site doesn't work because of that missing browser feature, then i will have to go buy somewhere else. it doesn't matter how much leverage the site has if i can't use it.
