In this case, what's more likely is that some customers will see the extra cost for IE6 as an unfair charge and just not use your services at all. I don't agre

In this case, what's more likely is that some customers will see the extra cost for IE6 as an unfair charge and just not use your services at all. I don't agree with them necessarily but put yourself in their place: They are not responsible for the state of Internet browsers and for Microsoft's low browser quality. So if you apply this otherwise good practice, make sure you communicate it well and price it very transparently. After selling someone of the wonderful benefit of a beautiful web application or site, it's always hard to backtrack and say that standard web applications like browsers actually can get very clunky and that some will cost a lot to support.