I haven't seen this discussed before but I might have missed something.

An easy way of selecting what content in a course that is "active" would be great.

In eStudio we have a tickbox for chapter, page and element so you can "remember" for instance a chapter.

This is very useful for testing different ways of presenting the same content or for having a course with most content the same for everyone but one or two chapters that are specific to specific groups.