The premise of Open Web App that I WANT to install and application in my browser. I don't want to do this because this ties me and the application to the browser I am CURRENTLY using. I don't use one browser. I don't use one machine. Today I regularly use three machines -- one MacBook, one iPhone, and one Windows laptop -- and four browser instances -- two of FireFox, one of Safari, and one of Internet Explorer. Tomorrow I expect to be using even more machines -- iPads, Android pads, setup boxes, Wii, etc. I don't want to be tied to one machine and one browser -- even if I can choose which ones. I want to be free to sit at any browser on any machine and just use an application and my data.
What I really want is for applications and data to be separated so that I can pick which application I want to use today to surface (visualize) a data repository. More on that another day.