As a long time user of ad blockers, I welcome this news. Remember when Google used to make a big deal about their unobtrusive contextual text ads? Yeah, those were good times. Now the rising popularity of floating overlays, interstitials, on-click popups and autoplaying video ads, not to mention the omnipresent "like", "tweet", "share" buttons that track your browsing history and violate your privacy — it all makes using the web without ad block a miserable experience. Oh, and by the way, ad networks so frequently get hacked and serve malware to unsuspecting visitors that the old view of "if I only visit reputable sites I won't get infected" no longer applies, and ad blockers become essential if you want to keep your computer malware-free.
More broadly, however, this is a strategic shot across Google's bow and an attempt to hit them where it hurts the most. What worries me, though, is that it also makes the web platform less attractive to publishers, pushing them into Apple-controlled channels (App Store and Apple News) and therefore threatening the open web.
With iOS 8, which introduced randomized wi-fi MAC addresses to prevent tracking people's locations in stores and such, but left iBeacon as a sanctioned alternative, Apple was sending a message to businesses: "if you want to track our users, use our technology".
Ad-blocking extensions will only work in Safari, they won't affect Apple News or third-party apps. In this way, with iOS 9 Apple is sending a message: "if you want to show ads to our users, use our technology" (Apple News and iAd, or App Store).
So don't miss forest for the trees — Apple is an 800-pound gorilla fighting a cold war with Google over ecosystems and content distribution, and end users are mere pawns.
