Overleaf - The online platform for scientific writing. Overleaf is free: start writing now with one click. No sign-up required. Great on your iPad.
CodeShare.io - Realtime code sharing for developers
TeXstudio - TeXstudio is an integrated environment for writing LaTeX documents.
Code.gov - Share & reuse open source code from the Federal Government
LyX - LyX is a document processor.
Code2Flow - An easy solution to create product flows.