Sutle - Save and organize resources into a directed learning path.
Gigasheet - The cloud spreadsheet built for big data.
Golden - Mapping all human knowledge
Airtable - Airtable works like a spreadsheet but gives you the power of a database to organize anything. Sign up for free.
Resource Center by Userflow - Userflow's new Resource Center lets your users access help directly in your app.
LearnAwesome - Humanity's universal learning map