To see my personal blog (on which I post a 4-8-page essay each month) click here.
As part of my work for Facebook, I wrote the first formal specification for the PHP language. This spec is available to the public at https://github.com/php/php-langspec. I also wrote one for Hack, Facebook's strongly typed language that is built on PHP. That spec is available at https://github.com/hhvm/hack-langspec.