Quip is aiming to fill the gap for productivity software in the mobile space.
The advent of smartphones and tablets has meant we can take work with us wherever we go (whether or not that's a good thing is up for discussion). That said, you're not going to get all that much work done without a decent productivity suite or, at the very least, a word processor. Microsoft's working on putting Office in your pocket with mobile versions of Office 365, but it's not a solution that works for everyone. Quip is hoping to offer an alternative with its own word processing application.
Quip describes itself as a modern word processor that facilitates the creation of "beautiful documents on any device." Started by former Facebook CTO Bret Taylor and his former Google engineer Kevin Gibbs, Quip automatically formats documents to the size of your screen, be it smartphone, tablet or desktop, and works offline, syncing whenever you have an internet connection. It also allows users to interact with documents, so you can turn a bulleted list into a checklist or meeting notes into a group to-do list. Mentioning another document (using the now popular @mention method) will result in a link back. Quip's also made sure to pack in plenty of collaborative features including the ability for multiple users to input data into the same document at the same time. There's also a more collaboration-friendly interface that sees documents and messages combined in a single 'thread' of updates. Messages and edits, called 'diffs' will appear in a pane on the left-hand side of your screen with the document itself will occupy the rest of the screen.
Documents aside, Quip supports shared folders, so you can easily access documents from friends and push notification whenever there's activity in one of your documents or when a recipient opens a document for the first time. The app is only available for iOS at the moment, though Quip promises an Android version is on the way. It's free for personal use and charges a subscription for business users.