My intention is to say that systems of a particular type allow users to express ideas on them. I wanted to give the concept a more concise/general name, as a title for such systems.
I called them Expressive Systems initially, but I realise that this may not be correct (it may, I don't know) because this seems to mean more that the system is able to express certain things on its own. This isn't even close to what I intended.
Does the adjective "expressive" in this context mean what I intend to mean? If not, what form of the word (or other replacement word) should I use to express my intention?