@broccoli
Site gets a surge in traffic from content going viral or increased search traffic
There are two possible explanations:
- First and in my opinion the least likely, based on your description of Adsense's reaction it could be that they are seeing the traffic as not being valid, scrappers, bots, or purchased.
- Second, the more plausible scenario. When content goes viral it typically does not get the same level of engagement. Many users are clicking on the links to your page because their friends sent them a link, not as a result of "genuine" interest. They check it out real quick and move on, this isn't bad it is just a result of going viral. Many more people do ultimately engage with the content then would normally but the percentage of people seeing the content vs engaging with the content drops. As a result page views rise sharply but CTR drops, the total number of clicks go up as compared to a normal day. Given the rise in page views relative to clicks all the metrics get skewed, CTR, RPM and CPC but the revenue generated is more than normal just not what you would have expected had you taken your typical day's RPM and applied it to viral day's page views.
The above can be further compounded if the viral traffic is originating from a location that does not generate as much revenue as normal, say traffic from India vs the US. A sudden surge in traffic from India when your typical traffic is US/UK will send all you metrics into a tail spin. This isn't result of some sort of penalty, it is simply that the mix changes. I fundementally disagree with Mentat comment above.
If you have a surge of Indians (no offense) => bad for you.
If the surge is from US/Canada/UK etc => good for you...
There is nothing bad with a surge in traffic from India (given that it is legitimate users and not bot traffic).
Say on an average day one makes $100 a day from US/UK traffic based on on 50k page views (RPM = $2) and $5 a day from Indian traffic, based on 5k page views (RPM = $1) . The combined RPM for all your traffic will be $1.91. Now you get a 10x surge of Indian traffic, the resulting RPM will be $1.50. "Bad for you" right? No, wrong. because you still earned an RPM of $2 on the US/UK traffic so your $100, but instead of earning only 5$ from India, you have earned $50 that is $45 more than normal. Sure the metric have all dropped but the money in you pocket increased and ultimately that is all that really matters.