Steve writes, "My email list has grown very large over time (it's about 80,000 now). I'm sending out a non commercial email article of a religious nature. It covers a controversial issue which I believe may lead to some recipients flagging it as SPAM, (even though I have an unsubscribe button with my dedicated hoster). I want to be able to link to articles at various websites but I don't want those websites to be in danger of getting blacklisted. How do I avoid this?"
Steve, thanks for that great question. Controversial email topics are ones that tend to attract higher-than-average spam complaints and deliverability issues, but not always for the reasons you might assume. Fact of the matter is, millions of people sign up for email lists talking about lots of controversial topics every day. People don't typically report those messages as spam, because those messages are desired. If your mailings are generating a high number of spam complaints, you've got a bigger problem that you've got to address. Because of the topic of your email, it wouldn't surprise me to find that people "forge subscribe" other people to your newsletter. Somebody who wants to upset someone who is anti-religious runs across your site, and decidezs it would be funny to subscribe a bunch of other people, to get them all mad at you. Maybe even hoping to shut you down, get you closed down by your ISP for sending spam.
My recommendation on the best way to avoid that is to utilize confirmed opt-in (also called double opt-in) for your email signups. Just about every ESP out there offers this as an option. And any time you have a special kind of list that tends to have problems with forged subscriptions or other shenanigans, it can make a lot of sense to secure the list (and keep bad guys from messing with you) by switching to confirmed opt-in.
In a confirmed opt-in scenario, signup becomes a two step process. First, a subscriber would submit their email address on your website. Next, they would receive an email from your ESP or list management tool, asking them to confirm their subscription. The recipient clicks on the opt-in confirmation link in their email, validating that they were really the one who wanted to be on your email list. It keeps bad addresses off your list (as the confirmation email bounces harmlessly), and it keeps spam complainers off your list (because people who don't want to be on your list don't complete the confirmation step). Confirmed opt-in lists tend to have much lower spam complaint rates than other lists.
As far as not getting other sites blacklisted, the best thing you can do here is be really careful not to send spam, and not to do anything that will generate spam complaints in any significant number. That's why I suggest confirmed opt-in above. Beyond that, there really isn't much you can do. Some domain blacklists do indeed look for domains referenced in spam and consider them for blacklisting. But, this doesn't typically happen over a single spam report. Keep your nose clean, and it's not something you're likely to experience.
(There's a huge caveat here: If you're going to be talking about something that is referenced in spam all the time. Say, for example, erectile dysfunction medication, then all bets are off. Mail that mentions things like this are probably going to run afoul of spam filters in ways you'll have little opportunity to address.)
By the way, if you don't think forged subscriptions are a huge problem, please send me your email address. I'm kidding….mostly. I've been getting forged subscribe to crap for years, and it's very frustrating for both recipients and senders.