だって can be used when providing excuses or explaining something. I guess it often goes with もん (from もの).
No mistakes so far, I hope. But there is another conversational use for だって which I’ve begun to notice recently. I think it translates as something like ‘me too’ – I was reminded of this all because of my previous post. So I’ve been hearing things like:
If anyone could confirm this for me, I’d be grateful.