I had an interesting match the other day on 23 and Me. It was a good 12.6 cM match with a person who had relatives from County Armagh in Northern Ireland, as do I. On investigation, we discovered that our ancestors were from the same small village and that there were surnames in common on some of our families' baptism and marriage records.
There were two aspects that I found to be educational:
1. Although we had a solid match on 23 and Me, we did not match on Ancestry DNA, because our 12.6 cM segment has only 4 mega base pairs, below the Ancestry threshold of 5 MB.
2. More interesting, my match and I live about a mile apart in the same town in Northern Virginia. That means that a scrap of DNA from chromosome 22 that started in Derrynoose, Armagh, made its way on her side from Ulster to New Jersey to Virginia, and on mine from Ulster to Glasgow to Western Pennsylvania to Virginia.
So: My lessons of the week are that there is value in testing with more than one company, and DNA is persistent!
PS--Blanche, no match to your mother, I'm sorry to say!