The important thing isn't to respond to the irony, but to recognise it.

Of course one way to respond to something which is intended ironically is to take it at face value, but to do so ironically.   

This can get complicated. Especialy when other people join in

In the context of the Mudcat, it can get even more complicated when a post comes from an unfamiliar person, especially from a nameless GUEST, because that means that it can be virtually impossible to know whether a remark is intended ironically or not.