It seems that ISP’s in the continuing war against SPAM are now using excessive bounce rates to identify spammers which has a negative impact on ethical email marketers.
Excessive bounce rates are normally a sign of spammers with their unlimited capacity to generate email addresses which most are invalid thus generating large bounce rates.
Because spammers are getting more and more creative and dare I say in more and more successful in fooling the current spam filters ISP’s are now adopting a zero tolerance policy with mail servers that generate reasonable amounts of bounces.
Now you can argue that the ethical email marketers with their confirmed opt-in mailing lists would not generate too many bounces but wait what about mailing lists that are contacted infrequently or only once every quarter or even once a year?
Because of the length between email communications and the fact that up to 30% of email addresses within a mailing list become invalid after 1 year you are sure to get a large amount of bounces.
There seems to be no way around this change in ISP policy where in some cases you only need to generate a reasonable bounce rate after one email campaign to be banned indefinitely.
The only way I can see currently is to increase your email campaign rate to reduce the bounce rate if you have long periods between email campaigns (who knows what some ISP’s would measure as long but I am guessing anymore than a month between email campaigns and you are asking for trouble) but then you start upsetting the subscribers as increased frequency of commercial based emails is normally not a good thing.
I would keep you posted on developments.