37signals has a great post today on the complexity they face in managing code on multiple platforms (web browsers + operating systems) and on the decision to drop support for an old platform. In particular, they announced today that they will be dropping support for a browser that is more than five years old but which is still used by 6% of their active users. They decided that rather than have to write conditional code that supports that old platform, it was time to tell those users to upgrade to something that conforms to modern web standards.