[SageRaven]

I thought it was statistical filtering and crowd-sourced spam tagging (like Google's spam filter). I maintain a mail server for a client and Spam Assassin (edit: and greylisting) works well enough without blacklists enabled. Throw in a couple of extra Bayesian filters via procmail, and you're doing about as well as Google does.

[danielweber]

Greylists are murder on businesses that depend on receiving mail from new people.

I see SpamHaus as akin to a the Microsoft monopoly in the 90's. If your interests are aligned with them, great. And for most people they do a great job. But there a lots of small businesses who get caught up and nearly crushed. Because a listing on a blacklist can be murder for a business that depends on communicating with people over email.

[ios84dev]

Why are graylists that horrible? All it does is require the sending server to retry 5 minutes later; I don't see how that would have any impact on a business unless they are in the habit of being on the phone with new customers and asking them to send an email at the same time.

[danielweber]

Assuming the sending server does that. Maybe it takes a few hours. Maybe it doesn't. Small businesses can be a mess, and you can't say "well, your customers suck" when the client complains about how greylisting is working for him.

[bigiain]

I've seen many poorly written web form handlers that try to do SMTP themselves, and that clearly don't ever attempt to retry graylisted failures...

[vidarh]

Why in the world would greylists be "murder" on businesses? We use 10 minute greylisting, and I occasionally check the logs and it does not seem to ever cause us to lose e-mails from anything but spammers.