This is a very helpful thread. Thanks to you, Ann and Wilfred.
I have a total of 40 matches, shared cM 7-9, on Ch. 3 between 97000000 and 110000000. Of those, at least 31 have Irish ancestors, most from the southern province of Munster, and two have ancestors from Wales, not far away. Those who could identify a place of origin in Ireland all indicated Cork or Kerry. I have traced two of them to my paternal ancestors' home parish in West Cork. One of these has a strong match on ch. 18 as well and a solid paper trail to an adjacent village.
I eyeballed the diagrams in the paper and on Kitty's blog, and this does not appear to be a "hot spot" or "jungle." I am inclined to think that the majority of these matches are valid and that they originate with a distant common ancestor who lived several generations before the availability of Irish records, which are sparse prior to the 19th century.
It would be most helpful if there were a scale on the diagrams or a tabular presentation so that we could more directly compare our matches with the "hot" or "cold" segments or "jungles." Ann, do you know if such data exist?