Buzzfeed’s native advertising approach means there’s very little different between a filtered (left) and non-filtered (right) page.
Blockr provides a number of configuration options about what precisely gets filtered out.
Blockr’s unique feature is an option to block all media. While this may seem extreme, if you’re on a slow connection (like T-Mobile users roaming internationally on 2G or a bad hotspot network), or you have a bandwidth cap or are charged for usage, such an option keeps the web available without having to switch to a specialized browser—and, wow, do pages load even faster.
How content blocking works
The filters are written as a series of statements about what URL or URL pattern is to be affected, and then what behavior should take place against it. This includes an optional resource type, such as an image, document, a popup, and the like, so that only that kind of data is affected. (For all the technical details, the WebKit team’s Surfin’ Safari blog entry has oodles.)
For any matched item, it’s also possible to filter depending on whether it’s fed from the same origin as the webpage that’s loading it, or from a third-party site. Ad networks and other tracking systems have ways around this, such as running subdomains that are customized to the sites that are feeding them out.
Finally, a filter doesn’t have to block a page entirely. While it can do so, it can also just strip all cookies or strip specific CSS (Cascading Style Sheet) selectors. These two options have two dramatically different purposes. Cookies are one way to feed a unique identifier to a browser, which it stores and then sends back every time it requests a page or other item from the same server (or sometimes, same domain). Unfortunately, there are a lot of other ways to bypass the limitations of regular browser cookies by using evercookies and supercookies. Blocking browser cookies won’t prevent determined tracking networks from seeding other kinds of IDs. Apple could expand the filters to disallow access to some HTML5-based features that are used to keep a cookie persistent when it shouldn’t be set in the first place or after it was intentionally deleted.
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