As more and more mobile OSes are released, that means apps have to developed for more and more platforms; multiplying the workload and the cost to both create and maintain any mobile app that you want to be available to anyone. Luckily, the web offers us a more standardized platform. (And before you cite differences in browsers: browsers are free and much easier to change than hardware, and there may be some minor discrepancies but the base technology used for development is still the same across the board). While there are obvious drawbacks (available data connection, bandwidth, integration with device-level features), many of those do not have that great of an impact for a lot of applications or can be circumvented with HTML5 APIs. One hurdle that HTML5 doesn't solve (at least, not that I've seen) is to run a web app in a way that the user experience is the same as if they were running a native app; meaning the removal of the browser chrome (address bar, browser menu, ...
Lessons learned and interesting tidbits from my adventures in web development