Once upon a time (2012), when life was simpler, I was informed that my Y-DNA showed I belonged to haplogroup J-P58, where J was a major haplogroup and P58 was my  terminal SNP identified by testing as of that time.  I felt then that all my fellow P58 males were my kin somehow.  Since then FTDNA has made enormous strides in slicing and dicing the branches of the Y-chromosome haplotree through its Big Y 500 and later its Big Y 700 tests.  Currently I am located in J-M304 => J-M267 => J-CTS12238 => J-Z2217 => J-L620 => J-PF483 => J-L136 => J-P58 => J-CTS9721 => J-S4924 => J-L818 => J-L816 => J-ZS2728 => J-ZS12186 => J-ZS12183 => J-ZS12187.   There I sit, alone on my own twig of the haplotree.  I confess I do find the science fascinating, but it has not enabled me to find a single Y-DNA relative.