Slack - A messaging app for teams who see through the Earth!
Todo.txt - Track your tasks and projects in a plain text file, todo.txt. A todo.
MS SharePoint - Share, organize, and discover information with Microsoft SharePoint. Learn about SharePoint Online, OneDrive for Business, and Apps for SharePoint
Task Coach - Task Coach is a simple open source todo manager to keep track of personal tasks and todo lists.
Jostle - A new kind of employee intranet that drives engagement & workplace culture. Achieves social participation in work relevant way. Participation rates are over 85%.
Strikethru - Strikethru is a kind of to-do list notebook for managing work lists and staying updated with the important tasks.