In general, I think that there is an important conversation to be had about how this newly proposed cacheing tier would effect the overall cat and mouse game between tracking networks and ad blockers on mobile phones.  Since the web community is being asked to choose to adopt a new technology, I don&#x27;t think there&#x27;s anything wrong with trying to reason about what would be technically possible to achieve in terms of tracking tech with this architecture.  Here one rough estimate:<p>If ads are all served locally (from a single domain) then it becomes technically feasible to utilize a short-lived rotating mutation URI generation scheme.  Under such a tracking system each ad unit URI would be instantiated &quot;just in time&quot; to redirect a certain amount of load after which it would expire away.  This JIT transient URI generator could be aware of the domain&#x27;s application routing table so that it can dynamically spin out each new tracking&#x2F;ad unit URI in a camouflaged form.  In other words each URI could appear to be only a mutated variation of organic cached content.<p>In computer security parlance this would establish a &quot;covert channel&quot; on top of HTTP via a timing attack vector (extremely short-lived URLs).<p><a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Covert_channel" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Covert_channel</a>
<a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Timing_attack" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Timing_attack</a><p>I would imagine that ads propagated through such a system would be pretty much impossible for an ad-blocker to identify within a low-enough latency window.  In other words by the time the ad unit&#x27;s URI is discovered by a blocking server and it&#x27;s clients are notified the URI has already vanished as if it never existed.<p>What&#x27;s I find slightly humorous about this approach to tracking is that the scheme would closely resemble several of the &quot;blackhat SEO&quot; techniques which are frowned upon by Matt Cutts&#x27; &quot;Quality Guidelines&quot; for example &quot;link schemes&quot;, &quot;automatically generated content&quot;, &quot;cloaking&quot;, and &quot;sneaky redirects&quot;.  Surely it&#x27;s unfathomable to think that Google would one day resort to such forms of trickery in order to confuse other search engines :)<p><a href="https:&#x2F;&#x2F;support.google.com&#x2F;webmasters&#x2F;topic&#x2F;6001971" rel="nofollow">https:&#x2F;&#x2F;support.google.com&#x2F;webmasters&#x2F;topic&#x2F;6001971</a><p>By the way this is only something I came up with earlier today and definitely not something that I&#x27;ve even heard discussed although I&#x27;m not in the advertising business myself.  In other words it&#x27;s entirely possible that I could have missed something here.