Safari content blocker extensions, which provide the ability to selectively prevent code from loading on websites, were previewed at WWDC 2015 as part of the developer sessions. Though they have many potential uses, the most obvious is for creating ad-blocker plugins for the iPhone and iPad. Rather than targeting ads, however, what Apple seems to be targeting here is all the JavaScript code that typically comes with ads and slows down performance. Dean Murphy gave them a try and shared his results on Murphy Apps:

After turning off all 3rd party scripts, the homepage took 2 seconds to load, down from 11 seconds. Also, the network activity stopped as soon as the page loaded so it should be less strain on the battery.

The subject for his tests: iMore.

To answer the obvious questions, yes. Everyone here and at our network, Mobile Nations, saw it. Everyone here and at our network were also well aware of it, and have been working for months already to improve it. That we haven't made it further, faster is an indication of how hard it is when you're talking about websites visited by tens of millions of people, and companies that employ more than a dozen writers. Of course, everyone here is going to continue working to find better, smarter ways of solving the problem, because that's our jobs. I'm sure other large websites are doing likewise.

A few additional observations:

  • Apple isn't just giving developers—and ultimately customers—a way to kill parts of a website they don't want to load, and thus improve performance, they're forcing developers to make high-performance content blockers so the medicine isn't worse than the disease.
  • Add content blockers to the list of things, along with switching to native code and bringing articles into apps, that major tech companies are doing to speed up the web experience.
  • Ad blockers will no doubt be plentifully available come September when iOS 9 launches.

Now, this was fun little project to mess around with, but it does give me a moral dilemma. Do I care more about my privacy, time, device battery life & data usage or do I care more about the content creators of sites I visit to be able to monetise effectively and ultimately keep creating content?

I don't block ads because, as someone who works for a site that has ads, I understand the cost of content and the current realities involved in paying for it at scale. (I don't skip podcast sponsorships—the ultimate in native, intercept ads—for the same reason).

But not everyone feels that way. Mobile ads already perform far, far less well than desktop ads, which perform far, far less well than print ads. As mobile becomes more popular, revenue goes down while expenses don't. Ad blockers will no doubt hurt revenues further.

What happens at that point is hard to say. Membership-based content might increase, though fewer and fewer people seem willing to pay for content of any kind any more. My guess is ads will evolve to become more "native", either towards sponsored content or towards flatter embeds. In the best of worlds, that'll lead to better designed, better implemented, better performing ads for everyone.