Now you see it, now you don't.
Maybe groups of users interact with your product in two different ways. Perhaps some need varying information to use your product. There are several ways in Confluence to display conditional content within your documentation. For example: you can create a documentation guide for administrators, or a user guide for people using your iOS app. The key is to separate content as your team writes it so you can segregate it when you publish your documentation. Some approaches involve merely separating variations of your content within pages, spaces, or set of spaces whereas others allow your content to be displayed and published based on definable conditions.
Two options for handling variants of similar content are to display varying content in the same space, or in different spaces. 
To only display the appropriate variant for a given user you can use content hiding macros.
To use a different variant for your help site and print publishings, you can use the Scroll Only and Scroll Ignore macros in Scroll Exporters.
For conditional content management, Scroll Versions give you the tools you need. You can display variants of content and entire pages based on one or more attributes.
Separate Content Within One Space or within Separate Spaces