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After the inaugural day of Apple’s latest operating system version, which permits new extensions for blocking content in Safari browsers, two apps that do just that shot to the top of the paid downloads.

Peace, a $2.99 ad-blocking app created by former Tumblr engineer Marco Arment, currently sits at first place in the iOS paid apps, bumping Microsoft’s Minecraft. A similar app, Purify, built by developer Chris Aljoudi, is at fourth place. A third, Blockr, is the 28th most popular, as of Thursday morning.

The apps, once activated, strip ads and tracking cookies out of the Safari browser on iPhones, but not other browsers, like Google’s Chrome, or within apps. Apple enabled them with iOS 9, which debuted on Wednesday. Publishers, particularly smaller ones, have worried that Apple’s move may spark an uptick in mobile ad blocking, curbing critical display ad revenue.

It has been less of a concern for big ad-supported tech companies like Facebook and Twitter, since their bread and butter, in-stream ads within apps, won’t be affected by the blockers.

Google, however, does make its cash from ads within the Web. The search giant has found a way to keep (read: paid for) its profitable text ads from being killed in previous popular content-blocking tools like AdBlock Plus. It’s not clear if Google has worked out a similar fix for these new iOS apps.

That said, the popularity of these apps is probably indicative of a first-day spike, not a sustained trend. ITunes ranks apps by total sales and speed of downloads, giving stronger weights to suddenly popular ones. Also, Arment, the creator of Peace, authors a blog frequented by hardcore Apple fans, which could explain the spike.