I have now looked at all my matches and all Best Mates' up to 7.9 cM. I have now hidden 30k of her matches and 26k of mine. It will be interesting to see how many remain in September. There is no way I have time to do the exercise on the other trees I manage.

I don't know what happens to hidden matches when they do the cull.

I am hoping that the ones that aren't marked do go. Though when I looked at my friend's hidden matches, there were about a dozen that I'd previously rejected who had put trees up and had common ancestors.

"Predicted relationship: 5th–8th Cousin
Shared DNA: 6.9 cM across 1 segment
Longest Segment: 8 cM"

So, do I lose a match like this, or keep it?
What does it mean?

I guess it must mean the segment was 8 cM's before the Timber algorithm was applied? Or it's a mistake.

Yes, if you click on the longest segment info, you will see that it says "In some cases, the length of the longest shared segment is greater than the total length of shared DNA. This is because we adjust the length of shared DNA to reflect DNA that is most likely shared from a recent ancestor. Sometimes, DNA can be shared for reasons other than recent ancestry, such as when two people share the same ethnicity or are from the same regions."

If you click on "Shared DNA" now when viewing a DNA match, you will see the figure for "Unweighted shared DNA" is given along with the other figures. This is the total amount before the Timber algorithm is applied. This only applies to matches with whom you share less than 90 cM's of DNA, as they don't use Timber on closer matches.

That's really useful, Kite - particularly for extra segments.