This is the word Paul Irish (@paul_irish) used to describe that jittering, stuttering effect that happens when you aren't syncing your animations with the monitor using requestAnimationFrame. Find out more about Jank at jankfree.com or requestAnimationFrame at CreativeJS.
It had been bugging me that using the former meant that this wasn't backwards compatible but it turns out I was totally wrong on this one. By using the attribute rather than a new tag, the styles were backwards compatible. They would still be interpreted by older browsers (although they would still spread out to affect the whole page). If they had been included in a new tag, older browsers wouldn't have read them. The affect of the styles on the page can be avoided by introducing an ID inside the block to be scoped (and all styles within the scoped block). That way, older browsers can continue to work fine while newer browsers that interpret the attribute correctly will benefit from the improved performance of having styles only affecting a small chunk of the page.
This is why I don't write specs.
Choose your elements wisely
The examples for improving selector performance for GitHub's diff pages presented in Jon Rohan's talk made me wonder "Do I really need all these divs?". Read more yourself. Also, I love the word 'Design-gineer'.
Pam Selle (@pamasaur) couldn't believe I had never heard of a porter beer. Is this actually a thing? Wikipedia seems to think so but then, Wikipedia can be convinced that Julianne Moore is Dudley Moore's daughter so I'll need more proof than that. Ale, stout, bitter, lager, all words I'm familiar with but 'porter'? Nope.
More than you'd think
I thought I had a fairly comprehensive list of all the CSS testing tools out there. Really. I've spent over a year researching and testing as many as I could get my hands on. There are even more. Phil Walton (@philwalton) made some excellent points around mocking content for tests that I'm going to have to follow up on.