Quite a bit, actually. Since 2007, we've gotten Javascript JITs, Canvas, WebGL, consistent box models, consistent event models, flexbox, CSS transitions & animations, CSS transforms, localstorage, IndexedDB, websockets, HTML5 audio & video, history.pushState, and several other features. And components (custom elements + Shadow DOM) are coming, and already implemented in some browsers.
Pretty much anything you could do in a native Windows app in 2007, you can do in a webapp now, except pwn your computer. Only problem is that the goalposts have moved: now everybody expects you to be able to do it on a phone as well, as well as access the camera, accelerometer (which you can do on the web, actually), contacts, calendar, and bluetooth hardware.