If you are familiar with SEOmoz than you know they publish quality informational articles. An article was written by Dr. Pete with an infographic of the Google Adwords landscape.
The biggest take away of the infographic is that shopping paid ads showed up on 19.1% of the queries that were used. Shopping ads is a relatively new feature but as you can see many companies have started to take advantage. Google has found yet another way to leverage their search engine to increase revenue.