The Rise of Aggressive Bounce Rates

After a slight lull, spam is back with a vengeance. Botnets (define) are growing in size and sophistication, enabling spammers to send more e-mail than could have been conceived of only a few years ago. This virtually unlimited capacity to send spam allows image spam and pump-and-dump stock spam to grow at an enormous rate. The ability to send tens, even hundreds, of message variants to the same recipient is very successful at getting through filters. The effect on ISPs and other e-mail access providers is substantial, requiring ever-growing resources just to avoid drowning in the flood.

In response, ISPs are doing what they’ve always done: tightening delivery requirements. The good news for e-mail marketers is the use of image spam and extreme variations in content mean that content filtering is less of a focus. The bad news is list hygiene and other chores related to best practices are becoming much more onerous. In particular, ISPs are increasingly aggressive about bounce rates. There’s a clear correlation between high bounce rates and spam, so it’s understandable ISPs utilize this as part of their defense.

Formerly, companies collected e-mail addresses with no clear plan for communicating with their subscribers. This was especially common with large, less agile organizations. At the start of a new marketing program, they’d find they had many addresses that hadn’t been used for months, even years. So long as the addresses weren’t too old, this wasn’t a problem. There’d be a high bounce rate on the first mailing, but those addresses were quickly removed. Things progressed cleanly from there.

Then, ISPs began tightening bounce rate requirements and implementing automatic blocking. These block systems offer zero leeway for one-off blips. This means marketers must now remain within the bounce rate requirements at all times, making older list cleanup much more difficult.

In recent months, some ISPs have become so aggressive about bounce rates that even legitimate communications preferences are no longer tenable. Senders are forced to mail more frequently than they or, in some cases, their subscribers would wish.

A common example involves subscribers on a one-year product-support cycle. A company can no longer e-mail annually to remind subscribers to renew. The bounce rate will cause blocklisting at many major ISPs. Companies with longer product life-cycles are in even more trouble.

The workaround is to send at regular intervals and somehow minimize the customer irritation and resulting list atrophy this may cause. Some customers are so engaged with a brand they’re interested in a monthly (or even more frequent) newsletter. Others can be convinced to stay if provided with enough interesting content. However, some people simply aren’t interested. They use a product, they may even love the product, but they really don’t want to be bothered by it on a regular basis.

The problem’s compounded by the fact aggressive bounce-rate blocking is more common at the free e-mail providers. Less engaged customers are more likely to register using their throwaway accounts at such providers. For these less engaged customers, the current rules do them a great disservice.

I wish I had a better solution to recommend. Unfortunately, I’ve been unable to find any truly effective workaround to this situation. Unless and until ISPs realize they’ve tightened requirements so far that some classes of legitimate e-mail simply can’t be delivered within the parameters they’ve set, I see no way to resolve this issue.

Until next time,


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