Looks like Yahoo has slowly and silently launched contextual ads for search within in its email. A while back I was searching for an email from ebay and when clicked on the magnifier icon to invoke search, the result was strikingly different. I could clearly see the advertisement/paid listing on the top of the results as shown in the picture below. Interestingly, I tried searching with other senders/keywords but the result did not include any paid listing!
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