It's slightly odd, but my appreciation of these jokes plummeted considerably as I travelled two hours over the border, from the Republic of Ireland to Northern Ireland. Browsing it in Northern Ireland, I thought the humour had suddenly turned folksy and tame, but I'm not inclined to look hard for Scots-Irish humour, especially when I was there.
But do read the status updates. I and many others found certain quotes outright hilarious. Most of the book can be read for free on Google.