Notebag - A keyboard-focused note-taking app that gets out of your way
Documize - Enterprise-grade wiki and knowledge management platform
iTunes - Media player, media library, Internet radio broadcaster, and iPhone device management application
HackMD - Fast and flexible, real-time collaborative markdown, inspired by Hackpad.
X (Twitter) - Connect with your friends and other fascinating people. Get in-the-moment updates on the things that interest you. And watch events unfold, in real time, from every angle.
ReadTheDocs - Spend your time on writing high quality documentation, not on the tools to make your documentation work.