Act and Microsoft Outlook can communicate with each other because an add-in has been enabled within Microsoft Outlook. That add in is called the ACT! Outlook AddIn.
So why do you need to know this as an Act user?
Because quite often add-ins become disabled within Microsoft Outlook and you need to know how to review what is enabled and what is disabled so you can take the appropriate action to make things work properly. Sometimes, to get them working it is as simple as checking or unchecking the appropriate box. Sometimes, you uncheck it and then recheck it. Think of it as having a checkered past. Kidding.
Here is a brief video I produced that will show you how to work with Microsoft Outlook add-ins.