These icons -- which represent establishments like Bankwest and JB Hi-Fi -- feature company logos rather than generic establishment icons.
This program, which is being launched in Australia for testing, differs from Google's traditional ad system. As the Sydney Morning Herald points out, these ads (or logos, really) are not purchased AdWords-style, but instead rely on number of impressions.
Additionally, companies must be deemed relevant by Google for their logos to appear. Google will determine the relevancy based on the context of a user's search, inbound links and event Wikipedia entries. Furthermore, if users don't interact with the location's ad -- by hovering over it and clicking through for more information -- it will disappear.
Google's goal is the highlight the most relevant businesses based on search. At least in Australia, Google is also charging some types of businesses less than others -- pricing is based on what value those establishments provide. So an ATM or gas station would be charged less per impression than a retail store.