I was thinking more about my last post, and what would happen if Yahoo changed its interface to something more Google-like. As I mentioned, there would only be room for a few home page links (email, finance, etc.) and the rest of the Yahoo! services would only be accessible via search.
So what happens to those other services? Well, if I search Honda Accord, perhaps Yahoo! autos shows up like it does now, as the top search result. Makes sense.
But wait, that shortcut isn't an organic result. It has an icon next to it, sits above the organic results, more links, etc. It's an ad. And since it is an ad, it competes with the other ads on that page. Accordingly, it should be measured against the other ads on the page for performance, profitability, etc.
I guess the hard question is what if there is opportunity costs associated with the shortcut ad? i.e. third party ads generated more income, performed better, etc. than the Yahoo! ad. Would they cut the service? Not sure, but it would be an interesting way to see if all of the "peanut butter" is worth keeping....