It's not bad advice, but there's a few very important asterisks to add to it.
|Nobody told the little robot that mailing inactives causes bulk foldering. :(|
- Asterisk: If you're seeing bulk foldering at ISPs like Yahoo and Gmail, keeping inactive subscribers around is a bad idea. Meaning: We know that these ISPs (and some others) look at engagement as a data point that feeds into the anti-spam equation. You've got enough issues overall that the unengaged subscriber pool is able to have a noticeable, negative impact on your inbox delivery. To fix: Attempt to re-engage, and then suppress, unengaged subscribers.
- Asterisk: If your inactive segment contains a bunch of subscribers that are very old, ones that you haven't mailed in a very long time, mailing these is a bad idea. Meaning: Any data you haven't regularly mailed is going to put your ability to get to the inbox at risk when you next mail it. A common kind of spamtrap involves recycling old addresses, making them bounce for 12-18 months before reconfiguring them to feed directly into a spam filter or blacklist. If you sit on a list without mailing it for 18+ months, you're going to have a higher spamtrap hit count than if you mailed it regularly and removed addresses that bounced. Mailing very old list data is a common source of Spamhaus, Cloudmark and other blacklistings. To prevent: Don't send mail to very old lists. If it's been out of commission for 18+ months, it's not safe to mail.
- Asterisk: If you've ever had problems with a big anti-spam blacklist like Spamhaus, failing to purge inactive subscribers is a really bad idea. Meaning: The type of bad addresses that got you in trouble with Spamhaus the first time, spamtraps, are hidden within your inactive subscriber segment. You typically are allowed a pass or two to attempt to re-engage those inactive subscribers when remediating the Spamhaus issue, but if you continue to mail inactive subscribers past that point, Spamhaus will see you "hitting" their spamtrap addresses again and you'll be back in hot water. To prevent: Attempt to re-engage, and then suppress, unengaged subscribers. Don't continue to send to unengaged subscribers after the re-engagement attempt.