Quick question: If you wanted to search this web site for a product, where would you click?
Maybe you managed to stop yourself in time, realising that the field at the top right is in fact a newsletter sign up form, not search. But I’m sure that they must have many other users who type search requests in that field. The fact is, we have certain expectations about where certain items will be on a web page. As a designer it makes sense to cash in on those expectations rather than try to subvert them.