Here's a reversal pretty much nobody saw coming: What used to be regarded as one of the most skippable forms of advertising -- custom content -- is now being held up by many in the industry as the thing that just might save advertising from all manner of ad-avoidance behavior, including ad skipping and ad blocking.

Before custom content was called that, of course, it went by advertorial (what, nobody liked "edvertising"?) in the heyday of print media. A newspaper or magazine advertorial was, for many consumers, something to rush past as quickly as possible. The worst advertorials -- with their fugly design, off-brand typefaces and tone-deaf language -- practically screamed "Ignore me!" even if you didn't notice the intentionally tiny warning label (e.g., "Special Advertising Section"). Meanwhile, the broadcast equivalent of advertorial, the late-night infomercial, was the redoubt of elderly shut-ins and insomniacs of all ages.

But that was then, and this is now. Though crummy advertorials (and infomercials) still exist, in the digital and social universe, more and more custom content is being built from the ground up to be truly compelling. "Brands have now discovered that together with the right partner they can create content that's just as engaging as some of the traditional media," says Andy Seibert, the former president of SmartMoney who now serves as chairman of The Content Council, the content marketing industry group, and whose day job is managing partner at custom content shop Imprint.

The thinking is that if brand messaging can be "just as engaging" -- i.e., wanted -- as quality editorial content, then consumers won't scramble for ways to avoid it.

That sounds reasonable, right? But how reasonable -- and how doable?

Let's break down the arguments for and against the idea of content marketing as the ad industry's savior.

Point: When it comes to branded content, marketers aren't quite there yet. Just ask Cannes.

For the second year in a row, there was no Grand Prix awarded at Cannes this past June in the branded content and entertainment category -- a signal from the jury, as Ad Age's Maureen Morrison wrote at the time, that "there's an overwhelming amount of content being developed, but none of it stands out."

Counterpoint: That's nonsense, and Cannes doesn't know what it's talking about.

As Maureen also reported, jury president David Lubars, chief creative officer at BBDO, declared at Cannes that, "The thing about this category to me is that it's not even a category anymore -- it transcends. It's just how the world is now." Indeed, much of the work entered and honored elsewhere at Cannes arguably fit the definition of content marketing, like Leo Burnett Chicago's "Like a Girl" campaign for P&G's Always and Adam & Eve/DDB London's "Monty's Christmas" for British retailer John Lewis. Both were mini masterpieces of storytelling -- standalone short films that were worth watching for their own sake -- and were loved and shared by millions of consumers simply because of the quality of their content.

As for content marketing that actually calls itself content marketing (or branded content or native advertising or sponsored posts or whatever your preferred term of art), plenty of stellar examples exist, from American Express' long-running OpenForum.com site for small businesses to The New York Times' T Brand Studio's widely shared "paid post" about female inmates that promoted Netflix's "Orange Is the New Black."

Point: Content marketing can't prove effectiveness like traditional advertising can.

Consider this, for example: In a report by the Content Marketing Institute and MarketingProfs titled "2015 B2B Content Marketing Benchmarks, Budgets and Trends," 86% of marketers surveyed said they're using content marketing, but only 21% said they're successful (or very successful) at tracking the ROI of their content marketing programs -- and 15% admitted that they don't attempt to track at all. Simply put, many content marketing initiatives are designed to live outside of the reach of traditional metrics, which is awfully convenient, isn't it? Can you really expect to solve a problem -- like ad-avoidance behavior -- if you can't judge the success of the supposed solution?

Counterpoint: You can measure content-marketing effectiveness and gauge ROI if you actually want to.

In fact, there are plenty of robust tracking solutions available from content-marketing-savvy software companies like Curata and Percolate, and there's no reason why various traditional metrics can't be applied to custom content. For instance, in the spring, The New York Times released the results of a year-long study of its paid posts that it conducted with Chartbeat, a company that many publishers (including Advertising Age) use to track unique visitors, incoming traffic from social media, engaged time, etc., on editorial content.

The report yielded good news and bad news for editorial purists at the Times: "While traffic on median-performing Paid Posts does not outperform traffic on median-performing NYTimes.com editorial content, some high-performing T Brand Studio posts received enough traffic to generate as much engagement as some editorial content on NYTimes.com," according to the study's summary statement. (The larger point of the study was apparently to prove to marketers that T Brand Studio is better at producing buzzy content than marketers are. To wit: "On Facebook and Twitter, T Brand Studio content outperformed advertiser-produced content by 1,613% and 504%, respectively. Google visits to T Brand Studio-produced content exceeded advertiser-produced content by 632%.") That "Orange Is the New Black" paid post, incidentally, was one of the top 1,000 articles on NYTimes.com last year. (Keep in mind that The New York Times publishes more than 300 stories every day.)

It's up to marketers to demand accountability from their content marketing partners, and more and more such partners are ponying up (see, for instance, the case studies for brands including Taco Bell and Virgin Mobile available at buzzfeed.com/download/casestudies.)

Point: Content marketing is hard -- hard to do well, hard to do fast, hard to scale and hard to distribute.

Even content marketing pros admit all that. "In the client-agency relationship, the process by which content makes it all the way to consumers is still very fraught with steps," says Keith Blanchard, the CEO of content marketing shop Teamstream Productions. "It takes a long time. Legal needs to see it, then PR needs to see it, then the brand needs to see it again after legal's seen it -- it's really counter to the idea of certainly the news function of timely, relevant content."

Mr. Blanchard, an agency (Story Worldwide), digital media (Thrillist) and traditional media (Maxim) veteran, adds that that's why many brands end up focusing on service-oriented content. "If you're producing something that's reasonably evergreen for a brand -- like if you're an auto brand, and you produce something on auto safety or auto maintenance -- it doesn't matter that it took three months to get it out there. So I see custom content leaning toward those kinds of things out of necessity."

Counterpoint: Nobody's saying content marketing isn't hard!

Which is more than fine with some content marketing players like Mr. Blanchard, who is making a business of working with brands to make better content faster -- as are publishers from BuzzFeed and Vox Media to The Atlantic and The New York Times, all of which have been growing nimble in-house content marketing studios that are meant to short-circuit brand bureaucracy.

It helps, too, that established publishers come with built-in audience, which most brands don't tend to have (Facebook fans notwithstanding). "That's why we work with partners who help with distribution, be it publishers or influencers, where we're creating content in partnership with them," says Steve Slivka, exec VP-executive creative director at Edelman Chicago. "Building audiences is not easy to do, and everybody is just reeling from that reality. There's so much out there that doesn't get seen and doesn't amplify and doesn't get reach." POINT Hey, content marketing is still advertising.

Let's not forget that an ad is an ad is an ad (apologies to Gertrude Stein). Sid Holt, the CEO of the American Society of Magazine Editors -- that stalwart champion of maintaining clear distinctions between advertising and editorial content -- says that if a consumer is really intent on blocking brand messages, then trying to slip them through by, you know, rebranding them has a high likelihood of backfiring. "If I was a user of, say, a mobile device attempting to block advertising," he says, "and the way that a marketer got around that was to send me custom content -- advertising disguised as editorial -- that would send me around the bend."Mr. Holt suggests that consumers balking at the often sketchy nature of digital ad delivery -- e.g., pop-ups, mobile screen takeovers and data-hogging campaigns that slow load time to a crawl -- is not the same as hating ads. "People do want advertising content," he says. "Like, one of the reasons people buy fashion magazines is to see the advertising -- people actually buy the product for the advertising."

For his part, Mr. Seibert of the Content Council says that it's a mistake to think of content marketing as a replacement for traditional advertising or a panacea for ad blocking. "In fact, I wouldn't say that in the custom content and content marketing that I'm even competing against ads," he says. "If done right, consumers love ads. So I think it's about the quality of what the industry is doing."

Counterpoint: (Not applicable)

Yeah, there's really no counterpoint to that argument.

Simon Dumenco, aka Media Guy, is an Ad Age editor-at-large. You can follow him on Twitter @simondumenco.