is RoboHelp a content management system?

No -- but I've used it like one, to a degree.

We use RoboHelp to author e-learning projects that contain pop-ups, which are easy to create once and re-use.

We also use conditional build tags to output different versions, which is a 'kind of' content management method to me, but I guess that's more about single source.

Well, the basic unit of information in RH is the topic. There are features to modify a topic and to exclude it from the final output. But you can't re-use part of a topic in another topic.

In a real CMS, you are writing building blocks from which the output is generated. Talking about online help, you can have one building block appear in a multitude of different topics. If you change one block, the changes propagate through all topics using this building block.

And don't get me startet abour robustness, reliability and the ability to handle large projects...

RH has several features which emulate a CMS, but the basic concept is completely different.

---Dirk Bock