"The important thing about XML is that it means that your software can be replaced. Now this may not sound like an advantage, unless you work for a software vendor who's being sued for antitrust, but it actually is an advantage for everyone. Because users have choice, there are fewer reasons for them to wait. And we can have diversity. Not only will there be desktop editing tools for Windows, but there will be equivalent tools for people who use Macs. Maybe someday Unix will be a great writing platform, or maybe something revolutionary and wonderful will come along that no one has ever heard of that you'll want to use to edit your Web site. In the software business you never can tell what's coming next, and with open interfaces the new things can easily be compatible with the old. "
I've been selling this idea for 3 years – Dave says it well.