I think its gonna take some time for this approach to standardize across browsers. Right now, Chrome is offering installable apps solely to allow developers to charge and to allow users instant access to webapps. IE9 beta is doing somewhat the same by having users instant access through pinning webapps onto the taskbar. Safari and Firefox will definitely have some solutions that are likewise. At the very core, your webapp will still be accessible through a url. And if you would like to extend your reach, why not make it as an installable app for Chrome, which just requires some extra manifest files. Unless you want that app to totally be at the client side? I hope i am not interpreting it wrongly.