Dropbox's collaboration-focused Paper tool just became much more useful if your team is juggling multiple schedules. The company's answer to Google Docs now has a timelines feature that lets you track who's working on a project and when. You can set milestones (such as due dates), assign members, write notes and attach relevant files. Your timeline view is flexible, too, letting you glance at the entire year or drill down to your team's week-by-week challenges.