Tornado

an open source version of the scalable, non-blocking web server and tools that power FriendFeed

MongoDB

a scalable, high-performance, open source, document-oriented database

Python Modules

an interpreted, interactive, object-oriented, extensible programming language. We also use some external modules: pymongo, feedparser, pygeoip, tldextract

memcached

an in-memory key-value store for small chunks of arbitrary data (strings, objects) from results of database calls, API calls, or page rendering

ArchLinux

a lightweight and flexible Linux distribution that tries to Keep It Simple

jQuery Plugins

a fast, concise, library that simplifies how to traverse HTML documents, handle events, perform animations, and add AJAX. We also use the plugins: timeago

Twitter Bootstrap

simple and flexible HTML, CSS, and Javascript for popular user interface components and interactions.

This could not be a list of every single piece of technology we use, these are just the ones we spent more time with.