What % of searchers generate what % of search ROI?

[shorebreak]

I've often wondered whether or not a very small percentage of searchers generates a disproportionally large % of search engine revenues. This belief is based on the observation that, of most people I know, there are two types: those who rarely/never click on paid ads, and those who *always* do, using paid ads almost as their primary means of search-based navigation.

Does anyone care to comment or share data anecdotes on this topic? Surprisingly, I don't think I've ever seen data on this mentioned here or elsewhere.

Thanks,
Shorebreak

[pavlovapete]

I recall being slightly flabbergasted when a young doctor in the family told me she didn't realise they were ads on the Google SERP. There is no correlation between 5+ years of university education and ad identification capability.

So I suspect there are 2 types of people in the world - those SEO SEM types who know that the weirdly formatted SERPs are actually ads and those that do not know.

From this I'd extrapolate a variation of the 80/20 rule. 80% of searchers click 80% of the ads bringing in 80% of the revenue.