Homepage.ninja - Homepage helps you to save and organize your links.
Knotable - Cut the noise out of busy email threads
Highlights by Learning Paths - Highlight, add private notes and tags across the web.
Scrapbox - A new style of note-taking that lets you create, discuss, and learn together in one self-organizing space.
Wikisend - Wikisend is a free online file and documents sharing administration that gives you a chance to share documents on the web.
Google Keep - Capture notes, share them with others, and access them from your computer, phone or tablet. Free with a Google account.