Well I assume people who have your Ancestry.com ID on their wikitree DNA pages (more properly on the profiles where both your and their DNA are shown shown, checked and found common relatives. Or possibly they could have looked at your tree on ancestry.com and see a common relative which you haven't added to Wikitree yet. It appears you haven't uploaded your data from Ancestry.com to GEDmatch yet, If you do that you'll be able to see lots of other people who might be relatives who aren't on WikiTree or even on Ancestrty.com.
But I don't know that there's any way to actually see connections on wikitree. You have to go to your DNA tester or GEDmatch or a similar organization and look. GEDmatch has the advantage of being free, though you can pay for some special things I think. On ancestry.com you need to go to the DNA tab and look at the connections they show and then go to the tree involved and see if you can recognize someone who is your relative. On GEDmatch you can see the actual match on a representation of chromosomes of you and your match which illustrates where they are the same and where they're different.
