Advertisers often complain about the drawbacks of online display advertising — and it’s not hard to figure out why.

Online display ad viewability, which is defined by the Media Rating Council as at least 50% of an ad’s pixels being in-view for at least one continuous second, is running under 45% these days — meaning that fewer than half of online display ads meet the definition of being viewable.

That’s actually a lower percentage than before; viewability charted closer to 50% in 2014, according to the global media valuation platform Integral Ad Science.

Because of these middling viewability rates, many advertisers look to e-mail marketing as the panacea. Not only is e-mail marketing inexpensive, the rational goes, it’s also more likely to attract and engage recipients.

But here too, the evidence is that there is mediocre visibility, too. And in this case, it’s actual willful ignorance.

According to the results of a study conducted earlier this year by business technology research firm Technology Advice, ~40% of the ~1,300 U.S. adults surveyed reported that they completely ignore marketing-oriented e-mails.

Of the ~60% who reported that they do open marketing e-mails, only a little over 15% do so on a regular basis.

Here’s a breakdown of the underwhelming stats that were gathered by Technology Advice:

• ~58% of recipients read from 0 to 25% of marketing-oriented e-mails sent to them
• ~21% read 25% to 50% of the marketing e-mail sent to them
• ~13% read 50% to 75% of them
• Just ~8% read 75% to 100% of them

In an attempt to “juice” these figures, marketers are experimenting with robust personalization in e-mails that become evident even before anyone opens them (e.g., personalization showing in the subject line), along with offering clearly marked discounts and other promo attractions.

In this regard, consumers do expect businesses to provide “value” in exchange for their attention, which explains by ~40% of the survey’s respondents are responding to discounts and similar promotional offers above all other types of e-communiqués.

But with such modest levels of people interacting with any marketing-oriented e-mails at all, there’s a question as to how whether these ploys to improvement engagement are just nibbling around the edges.

Because the reality is, there’s a big portion of the market that’s become jaded about e-mail.

Another approach seems counter-intuitive but just might be working better: reducing the frequency of e-mail solicitations from advertisers.  That theory is supported by the Technology Advice research, which found that nearly 45% of respondents feel that businesses would improve their marketing effectiveness by actually sending them less frequent e-mails.

A case of “less is more”? Probably so.