With Shopping Campaigns, Google lets merchants organize their online product inventory within AdWords, helping them create customized campaigns replete with tools to track a campaign’s performance. Now, the internet giant is inviting retailers to opt their campaigns directly into Google’s e-commerce partners’ own search results on their own sites.

In real terms, this means merchants can have their own Product Listing Ads (PLAs) show up when a consumer is seeking for similar items on e-commerce sites across Google’s Search Network, which include heavyweights such as Walmart, as part of its new AdSense for Shopping.

So basically a PLA can now “show alongside contextually relevant results, determined by the user’s search, the product category or the product name,” as Google puts it. In effect, this hugely extends retailers’ reach beyond that of Google.com or Google Shopping.

For example, if someone is searching for a product on any shopping cart site, they may now also be served with additional options from third-party merchants during the actual search.

AdSense for Shopping is restricted to a limited number of companies for now, with interested parties being invited to apply by completing this form here.