Track page speed, ad inventory, browser width/height and errors? All that is possible by realizing that Google Analytics lets you feed in arbitrary data and then allowing you to slice it to get new insights.
In beating the speed of lights negative effect on page load times we turn to Content Delivery Networks. Unfortunately the CDN industry is stuck in a 10 year old model with 10 year old technology. With the current focus on video they are not very responsive to what application and content sites now. This leads us to limit our use of CDNs to static images.