Vanishing Ancestry matches

[TonyV]

I usually narrow my Ancestry matches by parent which shows how many of each I have. I check daily and three times now I've found that there are less matches for the same parent than the previous day. Has anyone else noticed this or can offer an explanation? 

[Glen in Tinsel Kni]

I never bother accessing the breakdown page but I suspect the numbers change as some pull their results or make them private for whatever reason. I noticed a few of my bigger matches went the blank username route after protools landed and many had half sib matches so that might have been a factor and I find a new one every so often but have no idea when they went underground or how many there are overall.