It seems like the bus tour makes me stay a day behind the news, but I saw a post by Scott Karp in which he gave five reasons the mobile web sucks. It's what you'd expect. Wireless/Wi-Fi suck, the screens make it hard to view content/advertising and the mobile browser sucks. The first four are kind of true, but only when you're trying to think of mobile devices like any other computer. They have their own set of requirements and the experience needs to be customized. You can't cram a square peg in a round hole. But the last one, the mobile browser, is the reason the mobile web sucks. The iPhone helped show us that.
But the reason the mobile browser sucks is because the applications on the web aren't meant for devices, and that's fine. As I said, devices are a separate entity, and they should require a different site. I love the web-lite that most web sites use. When you're delivering content however, that's where rich mobile applications excel. With rich mobile applications you can mitigate a lot of what Scott complains about. You can easily add advertising that doesn't get in the way, you can create experiences that are tailored to small screens and provide a mobile experience that the user enjoys.
The key is making it easy to create mobile experiences from RIAs you're already building. The language, assets and platform should be generally the same so it's easy to move your product from "touch point" to "touch point" where the touch point could be web, desktop, mobile device or any other kind of device. That's been the power of the web (portability) but the demand for richness has allowed new platforms to spring up. Those next gen RIA platforms (for the most part) all allow code and asset reuse across devices and computers. That's very important and it's going to help speed the mobile experience along.