It amplifies the signal; makes the algorithms estimate a closer kinship & thus "see" a lot farther.A distant cousin that you connect to through that intermarriage will be a lot more likely to turn up as a match. The effect would diminish considerably at the 2nd cousin level & even moreso at the 3rd or 4th cousin level. If you were to count all of your kin you would have to count everyone on earth. We are very smart we have both book sense and common sense.
The app was created by three University of Iceland software engineering students for a contest calling for "new creative uses" of the Islendingabok, or Book of Icelanders, an online database of residents and their family trees stretching back 1,200 years.
This is certainly the case with descendants of my own French-Canadian ancestry.
My father is 5th cousin of himself, via a ancestor couple who seem to be unexpectedly reliable in connecting me to FF matches on my paternal side.
The ones in my age group would be my first cousins...which is far too closely related for dating, IMO.
I would just think it was kind of a neat coincidence, the same as if we had the same birthday.