>So, is quoting full FAQ content of one specific FAQ or full one message (few messages in the thread) in another forum is allowable? What is prohibited then?

What we need to protect is massive manipulations of the content. Thus, the content, here, does not refer to an individual item. So, yes, that is ok as per what you are stating as the example. What wouldn't be ok is to copy, for example, 10,000 messages and put that on your server for freely accessible access for all your corporate developers or for any non personal use.