The viewport is a direct window into what the user sees, and a lot can be learned by watching it. In my previous post I introduced Within Viewport and I want to discuss how, particularly through my Twitter app Signal~Noise, I’ve found it useful in making interfaces respond sensibly to user behavior.
A common solution for developers looking to increase their site’s performance is to load data on demand, for example using Infinite Scroll. But sometimes the scroll position isn’t enough — you need to know about the content on screen.
But what if a very popular site, one that nearly everyone would hit before reaching your site, loaded those libraries? I imagine the number of users running cached libraries would increase dramatically.