On websites that offer both Flash and HTML5 implementations of content, Safari users will now always experience the modern HTML5 implementation, delivering improved performance and battery life.

We recently replaced all spinlocks, OS-provided mutexes, and condition variables in WebKit with the new WTF::Lock and WTF::Condition — these new primitives have some cool properties.

WebKit on iOS has a 350 millisecond delay before single taps activate links or buttons.

Content Blockers extensions are enjoying a tremendous success on iOS and Mac — especially domain-based blockers.

JetStream 1.1 fixes bugs in two existing tests and adds a new test to replace the oldest and smallest test in the latency component.

Describing content blocking rules in a structured format ahead-of-time, rather than running extension-provided code.

A new JavaScript benchmark test suite that codifies what our de facto process has been — to combine latency and throughput benchmarks.

We are pleased to announce Speedometer, a new benchmark that measures the responsiveness of web applications.

Making CSS faster and more scalable is an area of research in the WebKit project.

One of my concerns last year was that while WebKit was getting faster on common benchmarks, some operations were getting slower as a byproduct of new features and optimizations.