I thought so, Very interesting. Found also this: http://www.eupedia.com/forum/threads/25236-Haplogroups-of-European-...
And not just Canute and the English kings buried at Winchester Cathedral, but now also Eric IX Jedvardsson "Saint Erik" King of Sweden from Sweden:
http://www.thelocal.se/20140423/scientists-to-pluck-crown-from-dead...
There is a man who claims paternal descent from Erik Christoffersen Løvenbalk, Prins, illegitimate son of Christopher II, King of Denmark. I don't know if his claim can be verified, but until now it's been the closest I've seen to the old Scandinavian kings. It will be very exciting if they can get yDNA from either Eric of Sweden or Gorm of Denmark.
Well, I have used DNA to find relatives, and its exciting to be able to confirm relationships.
Y-DNA: Can prove that you belong to the same paternal line (fathers-fathers..) This test can only be used by males.. To further prove relationships you need to test at a level of minimum 67 or even 111 (And also markers called SNPs).
mt-DNA: Can prove that you belong to the same maternal line (mothers-mothers). Can be used by both men and women.
Autosomal-DNA: Can prove closer relationships across all lines (all ancestors). Can be used by both men and women.
X-DNA: Can help you sort out where your autosomal and maternal matches belongs.. Males inherit only X from their mother, but women inherit X from both parents: http://www.smgf.org/education/animations/x_chromosome.jspx
In many norwegian sources only the father is known, and some baptisms it just says "Jons sønn døpt.." (Jons son baptized..), but it also happens that only the mother is mentioned (cases where the child was born outside marriage, without known father..).
One main difference that I experienced is that in english/norwegian records many parents are known as "Alice and Robert Sewell of Wymondham", the mothers name is Alice but no clue as who she was daughter of, and there could be more than one Robert Sewell in Wymondham. But in Norway it usually could say "Anna Rasmusdatter og Erik Jørgensen, Brekke".
In the norwegian example I then know that Anna was daughter of a Rasmus and Erik was son of a Jørgen, they lived on the farm Brekke where the child was born (one of the parents was usually from this farm..).
But back to the issue of DNA..
Dna test use FamilyTreeDNA in USA. https://www.familytreedna.com/
Det finnes tester som heter mtDNA (kun kvinner) Y-DNA (kun menn) FamilyFinder (både menn og kvinner).