As noted by the hosts on various episodes, The First Podcast has an uncharacteristically large Irish fanbase, when considering population size and density compared to other countries. Their podcast host provides them with detailed analytics, enabling them to have discovered this anomaly.
Dublin in particular is a city that features quite a lot of listeners.
Reaction to this Edit
The hosts don't seem to suggest that this is a bad thing, but merely a demographic curiosity, as all of them are located in southern California.
Lars and Joe have discussed future plans for a meet-up with the fans in Dublin, provided said fans take care of any and all expenses. They found humor in the idea that it was a rather illogical place to host the first meet-up, given the far more normal choice of somewhere in southern California.