Individuals identified by DNA testing as closer than the fourth cousin range haven't responded when I email to say hello. People who are identified as more distantly related have all responded, some quite enthusiastically maintaining contact. Perhaps when the genetic relationship is known to be closer, people fear that they'll feel a sense of claustrophobic obligation.
In a way, this is consistent with something I felt historically about some second cousins and most third cousins, I felt they were family, but I didn't have an interest in really connecting with them. I preferred my large first cousin family and, at the second cousin level, cousins who were multiply related to me. But I also felt that I was supposed to treat the more distant cousins like family, even though I didn't really feel a sense of emotional kinship.
On the other hand, encountering people who are 4th cousin or even more distantly related seems more like a fun coincidence unburdened by a sense of familial obligation.
Other genealogical amusements.
I asked my mother if she knew the maiden name of the wife of one of her older, American-born first cousins. She explained that the woman came into the family via an arranged marriage to her cousin, imported from the family hometown in Sicily, an engagement that was undertaken sight unseen.
I asked again about the woman's maiden name and she laughed. The name was the same as my mother's maiden name, though she said that the woman wasn't a cousin. Well, not a close cousin, but it seems pretty obvious the family went through the roster of second, third and fourth cousins to come up with a bride. Once I had more of her info, I did find the immigration record, the wedding record and her age. She was 28 when she came over. Must have been a hard-to-place bride. I think the same was true for the groom.
The marriage produced two children and lasted until the brides death in 2004. Her husband is still alive, and is age 96. The husband's elder brother, died last week at age 98. The brother's wife died in 2012, one month shy of her 100th birthday.