Matt Storms happened upon an interesting Google feature, presumably in testing. In a "site:" search for Macy's, he found where the number of items for sale found on pages is showing up in search results as part of the snippet. He highlighted the discovery on Google+:
Interesting SEO find today. If you have this with rel=publisher and schema star rating reviews you can take up some serious SERP real estate. Keep in mind I had to get past the page where you hide dead bodies on in Google which is page 3. Nobody goes to page 8 unless they are a SEO.
Search Engine Roundtable's Barry Schwartz pointed to the above post this morning, saying, "I am not sure if this is a PLA feature or if it is rich snippet related, I cannot reproduce it."
Nor have we been able to.
Additionally, in the same post, Schwartz points to a couple of other apparent, less significant tests Google is doing, such as a font size adjustment on result links and the cached/similar links moved to a drop down box next to result links.
We've reached out to Google for comment, and will update if we receive one.
The product count feature could be a helpful feature for ecommerce businesses and users who want to browse the biggest selections (or who don't want to spend time going through too many items).