It can be fun to figure out how to contact your “acquaintances” the first time this happens. You can't really email them, can you?
I had it when someone (or likely his partner) with the same (somewhat uncommon!) firstname.lastname@gmail.com used my email. I started digging and it turned out we both were/are PhD students, just totally different fields. Must have something to do with the name. I was happy that via the faculty site I found his "real" email. Nearly send him a really weird post card, I had only his postal address...
It wasn't as hard as I expected. In one case, I found her last name on an email and it had an additional letter, so I just modified the address to match her name (we were both first initial/last name).
In the other case I must have simply experimented with first initial/middle initial/last name, and that worked.
One is a minister in the Boston area, so it's not hard to recognize her inbound emails.
I had it when someone (or likely his partner) with the same (somewhat uncommon!) firstname.lastname@gmail.com used my email. I started digging and it turned out we both were/are PhD students, just totally different fields. Must have something to do with the name. I was happy that via the faculty site I found his "real" email. Nearly send him a really weird post card, I had only his postal address...