Breadcrumb Navigator Google Chrome Extension
It was available in the old Google toolbar, but since with Google Chrome there is no more toolbar, I have decided to code it myself:
The Breadcrumb Navigator Chrome extension allows you to browse any site in a breadcrumb-like way, or in a folder-like way (see the screenshots below for examples). The extension allows for navigating on subdomain level (code.google.com => google.com), path level (google.com/search => google.com), or a mixture of both (chrome.google.com/extensions => google.com). Engineering-wise the hardest part was to make subdomain navigation work correctly on sites like google.co.uk (sites with country code second-level domains ccSLD). Finally I ended up with hard-coding a list of all known second level domains after I was told by Malte Ubl (@cramforce) that browser vendors do nothing else. Give the extension a spin if you like.