irony appears to have recently been added and it currently has a whopping 5 questions. How many (on-topic, non-duplicate) questions about irony are we expecting?
I don't think that irony is really a needed tag.
- Is this an example of irony?—the question could be simply tagged rhetoric, which is the other tag being used for that question
- What are the similarities and differences between "irony" and "sarcasm"?—the question doesn't use sarcasm; why should it use irony?
- Is there a better / correct term for the de facto usage of ‘ironic’?—the other tags already classify the question
Does irony focalize an aspect of the question that is not already covered from other tags? If the answer is yes, then irony should be kept. As far as I can see, it doesn't add anything to the questions, but this is my opinion.
I could be wrong about this, but I suspect that English speakers (and maybe Brits in particular) might be more disposed to 'ironical' turns of phrase than some others.
Ironically enough, I've only recently posted that I don't see much point in using ironical instead of ironic, but in the preceding sentence it did seem to flow a bit better.
Anyway, the point is that although it might be somewhat tedious to have people keep asking whether some sentence is ironic, the fact is they do. So if my initial postulate has any credibility, there might be people wanting to gain a better insight into the phenomenon by searching for the word within EL&U questions and answer text.
So I say keep it, and let's see how useful it turns out to be over time.