For some random reason, I logged into my Yahoo Groups account today. I saw my mail was set as “soft bouncing”. Hmm, weird, I thought. Of course, it was my greylisting that had eaten a few messages. Yes, eaten. For some reason, it seems Yahoo doesn’t retry delivering mails which gets refused by a 4xx response, they just drop them. Ugly and stupid. I’ve now whitelisted yahoo.com in my mail setup, but that’s just because I want to get mails from said lists.
They have intentionally broken SMTP standards, something which really, really disappoints me; I thought they were one of the honorable companies, but apparently not.