[aarongustafson]

> For application-centric sites (For example, an internal admin app, or a B2B application where SEO and phones aren't the primary interface) why would I spend the money for the extra work?

If you have control over the end-user's environment, by all means do whatever you want. But when you don't (let's say your building an online banking site), you should ensure your real users can access it (and their money) no matter what.

Of course locking into specific technologies is why IE6 continues to persist (Intranets, South Korean banks), so that's some additional food for thought. It may not be a concern in your specific instance but it's a risk if you don't use web standards.

> It's almost as if your use case should determine your strategy.

:-) I wish more folks thought that way. When all you have is a hammer…