For the sake of providing a counter argument, not all publishers monetize page views; some simply want as many eyeballs as possible landing on their content. Additionally, it is almost impossible to guarantee that a request for your content results in a hit on your httpd process (even if you have the resources to send highly restrictive cache headers, browsers, proxies, etc. don't HAVE to honour them)
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For the sake of providing a counter argument, not all publishers monetize page views; some simply want as many eyeballs as possible landing on their content. Additionally, it is almost impossible to guarantee that a request for your content results in a hit on your httpd process (even if you have the resources to send highly restrictive cache headers, browsers, proxies, etc. don't HAVE to honour them)