There are many issues around digital advertising right now.

Transparency is the key one for many advertisers. P&G’s chief brand officer Marc Pritchard is leading the rallying call for agencies and others in the advertising supply chain to be more open about where advertiser’s media budgets are spent, and how much of the money actually ends up on a media plan after everyone in the chain has taken their cut.

Is adblocking digital advertising's biggest threat?
Is adblocking digital advertising's biggest threat?

Brand safety has also been back in the news in recent days with the revelation that YouTube’s vetting processes on its Kids channel are not up to scratch. This is leading to obscene comments appearing alongside children’s material and inappropriate material being served to its young audience. Advertisers including Mars and Adidas withdrew their ads from YouTube as a result.

A Mars spokesman told The Guardian, “We are shocked and appalled to see that our adverts have appeared alongside such exploitative and inappropriate content.” Hopefully the company is at least equally shocked and appalled that young children were targeted with said content.

And if it’s not transparency or safety advertisers are worried about, it’s fraud. And rightly so, in light of the discovery by ad tech firm Adform that a bot network called HyphBot has been generating fake traffic on more than 34,000 domains, to the tune of 1.5 billion daily requests, raking in as much as US$1.3 million (£1 million) in a single day, according to Adform’s estimates.

But while transparency, brand safety, and fraud hog the headlines, one other issue seems to have fallen off the digital advertising radar: adblocking. One senior ad tech exec I spoke to earlier this week believes the ad industry turns a blind eye to adblocking at its peril. Indeed, he told me, it represents the single biggest existential threat to the digital advertising business.

I think he has a point. So a couple of days ago, I spoke with Ben Williams, director of communications and operations at adblocking firm Adblock Plus. I wanted to try to get a handle on the current size of the adblocking threat.

When I shared the ad exec’s thoughts with him, he told me: “He is correct. It is on the rise at the moment, especially on mobile. While we’ve seen desktop numbers level off in the UK, we are seeing mobile numbers boom in the Asia Pacific region.”

One of the reasons for this growth in adblocking is the popularity of the Alibaba-owned UC Browser app, which comes with adblocking built in. And in the last two weeks, Williams told me, the company has seen massive growth in adoption of the Adblock Plus extension for another mobile browser, Samsung Internet.

Williams believes it’s only a matter of time before the Asia-Pac passion for mobile adblocking moves west.

So, what can publishers do about it?

“The best thing publishers can do is to work with adblockers,” he said. “All too often the approach is very combative, with the publisher putting a wall up in front of their content for anyone with an adblocker switched on. But all that results in is decreased readership and a bad relationship between the publisher and the user.

One of the best options is to serve ads that have been whitelisted by the Acceptable Ads Committee (which Adblock Plus established). That way, you can reach the majority of people who don’t have adblockers in the traditional way and treat the adblockers to a specialised experience.

If publishers do that, they will see that the adblocking demographic is a really good one, young, well-educated and happy to spend money online. If you put fewer, more acceptable ads on the page, you will probably find that big advertisers will be very interested in that.”

However they deal with the issue, one thing is clear: Adblocking remains a major threat to publishers’ future revenues. And while it hasn’t been in the news much lately, the size of that threat seems more likely to increase, rather than decrease, in the future.

Ignore ad blocking at your peril.