Something I didn't know about, and was excited to find out yesterday.
See, for the longest time, if you had a Github repository, you could only get a sense of how many times your code has been forked, or how many people "starred" it or were watching it. But to answer a question as simple as "How many page views did my repository get?", you had to arrange your own tracking.
Ilya took the next step, with the ga-beacon repo. He used the beacon image idea, and hooked it up to Google Analytics, so you could get all those nice graphs and tracking for free.
Once the repository became popular enough, it sounds like Github decided to just include this functionality natively. (So, if you own the repo, go to its Graphs > Traffic, to see the page views and visits).
Though you can still use his code, since Google Analytics provides more info and better graphs than the simple reporting included in Github.
So, this made me happy for two reasons:
Github has native pageview analytics now!
If your favorite site is lacking features, sometimes you can embarrass it into supporting them by coding them yourself, and having your code become sufficiently widespread.