https://hackpad.com/

Free for personal use.

Create and Organize
Take collaborative notes, share data and files, and use comments to share your thoughts in real-time or asynchronously. Every contribution is marked with the author’s name, so your breakthrough idea won’t get left behind.

Hyper Collaborative
Granular privacy permissions enable you to invite a single friend, a dozen teammates, or thousands of Twitter followers. Embed a Pad on your website to open the floodgates, while maintaining precise control with moderation and historical reversion capability.

Intelligent Execution
Break projects into subtasks, assign them to team members and append tags to create releases and milestones. Monitor your progress using to-do lists. Capture your context, objectives, supporting data, and files all in one place so your colleagues find what they need right away and stay organized.

Work from anywhere
Your content lives in the cloud, and is accessible everywhere (even offline!) by mobile, desktop and tablet.