One of our most popular features at Hackpad is the "tasks" feature. Most of you probably know that you can create a task by clicking the task button in the toolbar. There are actually two other quick ways to create tasks - you can use the ⌘-K shortcut (or Alt-K on Windows), or you can start a line with  (two square brackets) and Hackpad will automatically create a task for you.
Something we noticed pretty early in Hackpad product development is just how tough it is for groups of people to stay up to date on changes to their documents. That's why we've spent a lot of time making it easy to follow documents you care about and then receive succinct updates via email when others make changes.