It has been a strong principle of Google to show Rich Snippets for Products only if there is exactly one single product on the page. For quite a while, we have predicted that Rich Snippets will become a much more dynamic feature in Google, e.g. that it will be turned on an off depending on a particular query and depending on how it helps highlight important information in the SERPs. Now, for a few weeks, there has been a conflicting requirement for developers in the Google Developer documentation: At https://developers.google.com/structured-data/rich-snippets/products, Google says
Product markup should be used for a specific product, not a category of products or a list of products.
while at https://developers.google.com/structured-data/policies, they state that all products in a multi-product page are to be marked up (or none):
Each entity should be marked up using the relevant schema.org type, such as schema.org/Product for product category pages.
View original post 344 more words