I don't quite get why the author thinks that wasm will make asm.js irrelevant. As I understand it, what wasm brings to the table is mostly a binary representati

I don't quite get why the author thinks that wasm will make asm.js irrelevant. As I understand it, what wasm brings to the table is mostly a binary representation of asm.js, with the concomitant size advantages. If they're two different ways of encoding the same thing then I'd expect most toolchain and optimization work for one to benefit the other, and asm.js will continue to benefit older browsers for a while. What made asm.js a breakthrough was that vendors couldn't kill it by ignoring it - it's just Javascript, so it doesn't need explicit support to run, so ignoring it just hurts you in competitive perf benchmarks. Wasm IMHO is a smaller step forward, but I think the mapping is direct enough that a polyfill lib can handle deserializing wasm to asm.js - not ideal, but at that point it's unkillable again. Very different from {P}NaCl, which was very successfully killed by everyone except Chrome ignoring it. DISCLAIMER: I've read about these techs but haven't had a chance to use them in anger yet; apply pinches of salt to taste.