I seem to be noticing more and more online shops not using breadcrumbs in the navigation.

For example
radley.co.uk has no breadcrumbs
net-a-porter.com shows you where you are up to the product summary level using the sidebar menu (although it’s quite subtle), then there’s nothing on the product detail page
moss.co.uk using breadcrumbs up until the product detail page then stops
boden.co.uk does it all using the sidebar menu

I’m assuming these are conscious design decisions and not oversights – in some cases I suppose it’s obvious which category you’re in (a handbag is a handbag), and the top navigation is clear. The sites can look cleaner without breadcrumbs, and arguably not having breadcrumbs on the product page shifts the user forward to the basket, rather than backwards to explore more. That said, surely breadcrumbs can only help the use know where they are. And with Google using breadcrumbs now perhaps users will expect to find them on sites.

This is a good article on dos and don’ts, and types of breadcrumb design.

jungus.com/b/2009/03/18/breadcrumbs-in-web-design-examples-and-best-practices/