Adblock Plus, an ad blocker now used on more than 100 million devices, started out as an almost utopian idea a decade ago. Wladimir Palant, a 20-something developer who was annoyed with intrusive ads online, created it as an open-source project and quickly built it up with the help of volunteers who also wanted to make the internet faster, less cluttered and safer from malware.

Palant wanted publishers to make ads that did not “degrade" internet users with interruption and animation, he wrote on his blog in 2007. As Adblock Plus surged in popularity, he was able to turn it into a full-time job, increasing its staff to three employees in 2011 and housing it under a company named Eyeo GmbH in Germany. Its motto: “We want to make the internet better for everyone. Purging bad ads is a good start."

But shortly after that, in 2011, Adblock Plus was altered and became a tool that, instead of blocking bad ads, allowed ads it deemed “acceptable" to be seen, often for a price—a controversial move that has positioned it as a gatekeeper between advertisers and its huge user base.

Now, with a staff of about 70, the firm has moved even deeper into that business with an automated online advertising service that will allow more websites to place ads deemed “acceptable" in front of Adblock Plus users. It is a coveted group for advertisers and publishers: Users are often relatively young, well-educated, tech-savvy and hard to reach. But the introduction of the service last week ignited a backlash among users.

“It’s just the words we use for it that are confusing people," Ben Williams, director of communications and operations at Eyeo, said in an interview. “We are called Adblock Plus, and for branding reasons, we are not going to call ourselves something different. But if we could, we would call ourselves something like ‘web customizer’, because that’s really what we want to do for our users."

The new platform will essentially allow publishers to choose from ads Adblock Plus deems acceptable. They can then display these ads on their sites. In explaining the service on its website, Adblock Plus said it would help publishers make money when a user saw that “pre-approved" ad instead of a blocked space, adding that it had “been waiting years for the ad industry to do something consumer-friendly, but also industry-friendly".

Many users reacted with vitriol. “You either die a hero or you live long enough to see yourself become the villain," one Reddit user wrote in a thread of nearly 2,000 comments on the change. Reviews for Adblock Plus in Google Chrome showed a flood of one- and two-star ratings after the announcement. “Who do you think you are?" one user wrote. “The internet police?"

Adblock Plus has long had a list of criteria for what constitutes an acceptable ad—ads must be clearly identified and placed so they do not “disrupt the user’s natural reading flow", for example, and they cannot pop up, animate or contain images that enlarge.

For years, firms have been able to reach Adblock Plus users by creating ads that adhere to these guidelines and by undergoing a vetting process. The firm’s website says it takes about 10 working days for ads to be deemed acceptable, or “whitelisted". (The company says its new service will make that process almost instantaneous.)

The vetting includes an application, outreach from Eyeo, a signed agreement and a proposal posted to an open community message board. Adblock Plus explained that such efforts, along with monitoring individual ads and providing technical support, require funding beyond donations. Before it began whitelisting ads, Adblock Plus accepted donations and funding to become a company, although it does not disclose its financial details.

Adblock Plus says it charges only large entities, which it defines as those that increase their ad impressions by 10 million or more a month once they have access to Adblock Plus users. And Adblock Plus typically takes a 30% cut of the money from ads that would otherwise not be seen by its users.

Regardless, over the past few years, this toll has infuriated publishers and advertisers. As of June, Adblock Plus accounted for about 60% of the 220 million ad blockers installed on desktop browsers, according to PageFair, a start-up based in Dublin that develops software to fight ad blockers.

The new ad platform is alarming because it “allows them to do this at scale", said John Montgomery, executive vice-president of brand safety at the advertising giant WPP’s GroupM.

“It scares me," he said. “It makes me uncomfortable that Adblock Plus would be the arbiters of what is good and what is not good."

©2016/The New York Times