A few days ago Google migrated Products search to the forefront replacing Video search on the Google search pages.
People started asking questions, turns out many saw Products search for the first time.
Here's a few interactive visual aids, "What is" and "How to's". Enjoy!

explanation of the main Products screen
http://www.web20ref.com/r/RGScGprod.html

results screen explained
http://www.web20ref.com/r/RGScGprodRes.html

"what you can do with the feature" major walk-throughs
http://www.web20ref.com/h1/hshop.html