https://dev.37signals.com/page-refreshes-with-morphing-demo/ https://dev.37signals.com/page-refreshes-with-morphing-demo/ I'm not being snarky. What apps must

https://dev.37signals.com/page-refreshes-with-morphing-demo/ https://dev.37signals.com/page-refreshes-with-morphing-demo/ I'm not being snarky. What apps must be SPA's and why? I'm personally questioning where that line really should be.