Ciro Santilli Homepage: eli.thegreenplace.net/
Amazing systems programming tutorials. Whenever you Google a hard topic, his blog comes up.
Also has many great contributions on Stack Overflow: stackoverflow.com/users/8206/eli-bendersky
As of 2016, Eli worked at Google (reference). TODO before that, I had found his earlier info previously but lost it.
Eli focuses mostly on compiler toolchains, apparently with specific focus on
He also has some mathematics stuff, so cute: eli.thegreenplace.net/2015/change-of-basis-in-linear-algebra/