I don't know how good yahoo search actually is because I don't use it, but I agree with you about the strategy and business model.

I'm much more comfortable with building applications on top of infrastructures I pay for instead of being held hostage to the odd loyalties and uncertainties that come with ad supported services.

I may want to be yahoo's customer but I don't want to trick my own customers into somehow watching yahoo provided ads or rely on some other indirect means of helping them make money.

Amazon does the right thing. I hope they succeed.