(This post originally appeared on Forbes)

Here’s something I never seriously considered: including paid ads in the body of an email campaign.  Paid ads? You would think that in today’s world of advertising overload most recipients would be turned off.  Turns out they’re not.

At least that’s the conclusion from a new study commissioned by Powerinbox, a company that (surprise!) provides email marketing services and offers what it calls “personalized subscriber engagement” to some of the world’s largest publishers so that they can get their messaging out by – you guessed it –  placing advertisements in emails.

So there may be some bias here.  But I’m not sure that matters when you consider the findings. According to the study – which was conducted by Mantis Research, an independent research firm – 40 percent of the people surveyed said that having ads in an email didn’t bother them at all and – surprising to me – almost two-thirds of them said they would actually click on an ad.  Unfortunately, I could not find where the actual sample size of this study was disclosed.

Regardless of the methodology, the results are intriguing. Why aren’t ads in an email as big a deal as one would think?  Shouldn’t people be annoyed by them? The answer comes down to just one word: relevance.

Every marketer needs to understand the importance of relevance, which is why we try hard to teach that lesson to our CRM clients.  Trust me, I’ve learned this the hard way. Back in the day we would often “blast” emails to thousands of recipients, whether they cared about the information or not.  Ultimately that resulted in a lot of “unsubscribe” and “take me off your list you !@#$%*$#” responses. And those were the nice ones.

People don’t want to waste time reading useless stuff and will ignore messages coming from a sender that includes irrelevant information.  That’s why our best clients leverage their CRM and marketing systems to better segregate their data into multiple lists and then send out different emails depending on what is of interest to the recipient.  Yes, it’s more work, more content, more data management and more analysis. But it’s how effective email campaign management is done.

And besides…it’s what recipients want.  So let’s get back to including advertising in emails.

Of course, the study’s results varied by demographic. Older users – baby boomers – were least accepting of ads in their emails while over half of younger generations ranging from 18 to 37 weren’t bothered. But despite the generational differences, one thing was clear: as long as the ad was applicable to the reader then people were generally okay with it. In fact, 70 percent of Generation Z’ers (ages 22-37) would click through on a relevant ad and even those cranky baby boomers – at least 57 percent of them – admitted they would do the same.

“This data confirms what we have been saying all along: email is not dead, in fact it’s an extremely effective channel for advertisers when it comes to reaching a captive, engaged audience,” PowerInbox CEO Jeff Kupietzky said in a press release. “It also confirmed that content relevancy is critical. That’s why using email as a unique identifier, which takes into account known subscriber behavior, is far more accurate for one-to-one targeting than browser-based cookies alone, which can’t distinguish between multiple users of the same browser or device.”

Of course he would say that – it’s what his company does. But Kupietzky’s points are on the mark: relevance is key in today’s email marketing, even if advertisements are included in the message.