Excellent slides and yes you are right cross platform development of widgets is possible using a core set of code common to all platforms. One issue I have faced though is the different way the iPhone and Android treat scrolling ie they ignore the CSS "position:fixed" command whereas S60 behaves correctly. This makes it difficult to use the same code for all platforms if you want none-scrolling screen regions - I am working on a solution but its not fully working yet.

Thanks Robin for your feedback. And yes, we still need porting between some platforms. But that porting can be on the fly, using the same code. For example, you can use the body class pattern where you assign a class using JavaScript to the body tag depending on the platform. So, you can generate some different CSS per platform.

Your slides are very educational. Thank you very much. As your presentation has pointed out. Many vendors are expanding in this area. Great potentials!