Hils,

From your description of what you're trying to do, I agree that Outlook can provide some of the functionality you desire. If you have a access, SharePoint can also provide most of the functionality you're looking for:

• Assign tasks to other people (Can also send a message to the recipient?) Yes
• View certain people’s to do list, but not others Yes (Can be managed by varying permision and library levels)
• Prioritize tasks Yes (Low, Normal, High)
• Set due dates for tasks Yes
• Add tagging to tasks No (Can assign predecessors)
• Add subtasks No (Can assign predecessors)
• Add notes to tasks Yes (Description)
• Have the software send a reminder message just before a task is due Not sure (Have never used this function)
• Sorts tasks by person, date, priority, etc. Yes
• Have people “follow” a task (i.e. view someone else’s task, but not be able to edit it) Yes (Can be managed by varying permision and library levels)
• Link to an app that is password protected Yes
• Can the mobile app can let people view tasks and if possible, create tasks as well Not sure (Have not used with mobile app)