A clear majority -- 55% -- of North American consumers report occasionally unsubscribing from email lists, while a full 14% admit to frequently unsubscribing, according to Epsilon.

"North Americans are receiving a lot of content, and at the same time they're getting more and more selective about the kinds of emails they want to receive," said Kevin Mabley, SVP of strategic services at Epsilon.

By contrast, the majority -- 51% -- of Asia and Pacific-based consumers report rarely ever breaking up with email marketers, just 31% do it occasionally, and only 4% claim to do it frequently.

Exactly half -- 50% -- of European, Middle Eastern, and African consumers claim to occasionally unsubscribe from email lists.

Across the globe, irrelevant content and high frequency are cited by consumers as the two most likely reasons for unsubscribing.

"Companies stuck in a batch-and-blast mentality see email as a cost-effective medium, so they may abuse that privilege and end up turning off the consumer with too many messages or the wrong messages," said Mabley.

In particular, 67% of North Americans unsubscribed due to the irrelevancy of emails, 64% cited high frequency rates, and 50% attributed their decisions to fears that their email addresses were being sold or shared.

"The companies doing a better job managing their relationship with permission-based email recipients are taking into account consumer preferences and past behavior to make sure they're delivering content that's relevant," Mabley added. "They're also testing frequency and content to make campaigns more effective."

Notably -- compared to just 20% of Asia and Pacific-based consumers -- a full 48% of North American consumers unsubscribed because they could not recall signing up for emails.

On the bright side, Western-focused email marketers will note that the vast majority of North American consumers -- 87% -- along with 74% of Europeans still use email as their primary online communications tool.

Just 6% of North Americans -- compared to a whopping 28% of consumers in Asia -- think of instant messaging as their primary communications tool.

Also worth noting, social networks have yet to emerge as primary communications tools worldwide. For North Americans, a mere 4% listed social networks as their primary communication tool.

Conducted by ROI Research, the study is based on an April survey of over 4000 consumers in 13 countries.

According to Epsilon, email is also replacing other channels of communication. Over one-third of respondents have replaced traditional channels in favor of email for communications from banks -- 40% -- promotional postal mail -- 38% -- and telemarketing -- 34% -- while there is a desire for email to continue to displace offline coupons -- 14% -- and telemarketing -- 28%.

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