An underlying, unintentional, yet pervasive message at OSCON this year is this: while the web server is a proven platform for building applications, the web *browser* is a horrible platform for building applications. Browsers have a tough row to hoe to get where they need to be. The huge advantage they have is cultural: programming applications by default are assumed to be best done on a browser, especially "cross browser", no matter what pain is involved.
Please don't hurt the web! Use a productive client.
The combination of those could be significant.