One of my good friends discovered her biological half-brother on 23andMe who she had never been told about. They met up, and got along remarkably well, and have actually remained pretty close since! These things do happen. Glad you got something out of it, too.
Yeah, these experiences may or may not be rare. I was positing that they might be rare mostly to try to meet the person I was responded to halfway and because I don't actually have evidence one way or the other