Collaborative hypertext + productivity applications; see this Quip post for details
"It’s not visible to the consumer, but each cell inside the spreadsheet has its own Web address (thank you, nearly infinite amounts of cloud computing storage.) That means that, as well as interacting with other numbers in other cells to, say, add up a sum of restaurant receipts, the numbers can be linked from one format to another, like spreadsheets to documents. Mr. Taylor calls these many addresses “the atomic units” of Quip on the page, which are not “saved” to memory in a permanent sense, as much as “synched” to a cloud-based master repository for all the data.Quip: Make Numbers Dynamic, Too - NYTimes.com
The upshot is a more continuous style of communication, without clicking between one program and another. Even while in a document, the spreadsheet can also be broken out as its own product. In either form, collaboration is implicit, with people able to discuss what they are working on."