I found a great article by Maile Ohye entitled “SEO Tips for e-commerce sites“. Its a pretty large posting and has multiple embedded videos, some 15 minutes or more.  There are lots of articles about “Ecommerce SEO tips” but I especially enjoyed this posting not only because it is pretty substantial but it was written by a Google Employee.

rel=page issues with e-commerce sites

• A common issue where there are category pages on your e-commerce site where you have to hit the ‘next’ button to page through that category page’s products.
• To help with this, Google released in November, 2011 a new protocol – the rel=next and rel=prev – as a better alternative to the rel=canonical solution.

What about ‘out of stock’ products? What do you tell Google?

• Maile discusses maybe returning an HTTP 200 message, NOT a 404 not found.
• Maybe you don’t want to tell Google that product is gone forever (e.g. ‘404 error’) but rather that its still alive, just not available right now.