Avoiding being marked as spam, even if you're legitimate, is much a "dark art". At any one point your reputation could take a hit because you did something, and

Avoiding being marked as spam, even if you're legitimate, is much a "dark art". At any one point your reputation could take a hit because you did something, and no one will tell you what you did wrong. An ISP can just start redirecting your mails to /dev/null and you'd never find out about it until a user asks you why they haven't received a mail from you in 2 weeks. Malicious actors can also try and get you flagged as spam by artificially generating spam reports on you. There is no rule set you can follow that guarantees you're safe from ever being blackholed, it's all very fuzzy. Once you're hit with a ban, it's very hard if not impossible to recover. If you've been at HN for a while, you must have noticed that every now and then there are stories from Google users being mistakenly banned from their account for violating some rule that they don't even explain to them. These events happen to mailing lists as well, but there's even less of a recourse for mailers when this happens. Considering all this, I'd rather err on the side of caution and implement most of recommendations by Google, than increase my risk of being marked a spammer, and risk losing the whole project. > However, an occasional confirmation (say, once or twice a year) as they suggest would be just fine. You could even restrict those to just those subscribers who do not trigger the tracker. What is fine to you, is annoying to others. Just read the other comments on this story, where people commonly complain about receiving an email asking to reconfirm their subscription.