Prior to this change, customers who wished to disengage would have to delete their DNA completely.
When the change was first announced, there was some concern among Ancestry users that the number of shared matches would reduce significantly if many existing customers chose to opt out. Then users noticed “missing” matches when they went to review past notes and manual lists. It didn’t help that there was also erratic behaviour of the Surname/Location Search functionality.
It’s difficult to be sure about the impact without snapshot lists of matches before and after the change. Unfortunately Ancestry does not provide the facility to download matches to spreadsheet, unlike some other companies.
In July 2017 I personally recorded details about all my DNA matches on AncestryDNA. I repeated the exercise in February 2018 and again in May 2018. I used techniques I describe here.
It’s just luck that one of my snaphots was before the change, but it allows me to do some analysis of the impact on my own results of people choosing to disengage from matching.
So, how many matches were in my snapshot of July 2017 that *were not* in my snapshot of February 2018?
A grand total of five matches disappeared.
I don’t know if they opted out or if they completely deleted their DNA and closed their accounts. However none of these five had reappeared by May 2018.
I wrote a separate blog post with full analysis and breakdown of my total numbers. As I gained gained 2,394 matches over the same time period, the opt-out number is insignificant. As that post also shows that over 80% of my matches were below 10 CM, statistically these low opt-outs are most likely to be low CM. I could have been really unlucky that one or two of those matches happened to be close, but I happen to know that they were all 10 CM or below.
Between February and May 2018 a further two people disappeared from my match list.
Again, they were of minor CM.
I acknowledge that these five could have been very close matches for some existing customers seeking to solve mysteries. The impact to those customers is of course highly significant. But overall, this is not a worrying factor for me in my continuing use of AncestryDNA.