If all you care about is making websites that people using current browsers can see, there's already a rich, stable technology for that. It's called Flash. An

If all you care about is making websites that people using current browsers can see, there's already a rich, stable technology for that. It's called Flash. An extensible, semantic web markup standard is needed if you want to create content that can be consumed in all sorts of ways (e.g. text-only, search bots, future browser-like technologies, etc).