I have recently had a 37 marker Y chromosome test by FTDNA. The outcome so far is patchy, my surname is fairly rare around 2200 instances worldwide, over 50% in the USA, 25% in UK and 22% in Canada, the remainder mainly in Australia. The highest concentration in Newfoundland , which fits well with migration from Dorset as the highest UK concentration is in South West England. With bearers of the surname I have 2 no relationship, one with whom I share 33/37 markers, suggesting a probable relationship, as a paper connection is around 1600AD at the latest this seems reasonable. The strongest relationship 36/37 shared markers is with a person in Canada, it seems my ancestors and his were in Lincolnshire between 1795 and 1900 approx.
I believe the principal reason there are so few matches is that only around 10 people have take the test so far.