Call it anti-tracking and privacy software, bandwidth-reduction management, or ad blocking. By whatever name, it’s popular in desktop operating systems like OS X and Windows. A study released midyear found nearly 50 percent of U.S. and 40 percent of routine online newsreading consumers employed blockers. With the release of iOS 9, these kinds of filters can be installed in Mobile Safari.
Content Blocking Safari Extensions, as Apple calls them, are filters created by third-party apps. The apps either include a prefabricated and updated list, or offer options to configure which kinds of content to block, including whitelisting and blacklisting sites.
The filters start with a URL pattern using standard “regexp” (regular expression) pattern, which can match an individual page on a site, every kind of page or media of a certain kind, or patterns across all sites. An optional media type can be noted, too, like a document or video. Before Safari loads a page or item referenced on a page, it matches against these URL patterns. If there’s a match, the entire page or item may be blocked, or just an associated browser cookie or page elements defined by style sheets. Filters can also block content referenced on a webpage that originates from a domain other than that of the webpage.
This allows a lot of customization. Entire sites can be fully unavailable—blacklisted from loading. Or all bandwidth-consuming media (audio, video, and other types) can be suppressed on low-bandwidth or high-cost connections. Every app is approaching this differently.
Let’s roll up out sleeves and see what they can do.
Install and manage content blockers
Apple doesn’t include content-blocking extensions in iOS 9; it just lets them happen. They aren’t full-blown extensions, such as are available in desktop browsers like Safari. Those kinds of add-ons or plug-ins can add new ways to view media or control basic browser behavior. Instead, content-blocking extensions are a list of patterns and behaviors that a third-party app passes to Safari, which collects and compiles them from all enabled apps into a fast-loading filter set.
First, you need to get one or more apps. Since I’m writing this on iOS 9’s release day, only four content blockers are available right now. I beta tested several, and will update this article with more detail as they can be purchased or downloaded.
(Note that not all iOS devices are supported that can run iOS 9: only those with 64-bit processors. This excludes the iPhone 4s, 5, and 5c; the iPad 2, 3rd-generation iPad, and 4th-generation iPad; 1st-generation iPad mini; and the 5th-generation iPod touch. All later devices work.)
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