[hollerith]

>more and more stores put their coupon codes right in the header while you're browsing

By "in the header" you mean on the search-engine results page; don't you?

[jeremybencken]

actually, no, although that's an interesting place to do it. as a few others have commented, merchants like Newegg and Gap use something like a HelloBar to highlight their coupons in the header nav.