I wrote a
single post on a thread nearly 17 years ago and in return, I've received an email every year on my birthday for the last 16 years wishing me a "happy birthday".
I mean, there have been other forums, services, dentists, etc try to do the same thing in the past, but the birthday reminders usually either stop or just devolve into spam after a few years.
It's a small thing, but thought I'd mention how impressive the rate of return for one post and consistency of delivery has been to me.
Thanks for the happy birthday wishes, LinuxQuestions.org!