After years of holding out, Amazon is now participating in Google Product Listing Ads (PLAs). This is the first time ever that the world’s largest online retailer has joined in the pay-to-play format under Google Shopping.

Likely due to competition between the two, the shopping giant refused to participate in Google Shopping listings; but PLAs now dominate traffic from e-commerce product searches on Google. And as searches continue to shift more to mobile, Google’s status as the go-to search provider has only grown.

Though Amazon Sponsored Ads appear to be limited at this point – as various product searches yield limited results – it could cause problems for other retailers who don’t have the budget to compete with the enormous store.

Smaller companies that have PLAs will now be paying more in an attempt to compete with Amazon.com and have their listings show in the limited Google Shopping box on the SERPs page.

In addition, a company utilizing both Amazon.com and Google Shopping is competing with itself, with both ads potentially showing up in Google Shopping listings. Most e-commerce businesses prefer to bring traffic to their own websites simply because Amazon charges a percentage of sale. But because of its size, it will likely dominate Google Shopping.

Regardless of whether these ads are limited or become more prominent in Google Shopping, it’s even more crucial now for retailers to optimize their websites and products. Landing pages can increase relevancy, and having optimized products and landing pages can create a better standing in Google.

For Amazon.com stores, it’s now imperative to win the Buy Box and make sure products are optimized – not only to help sell on Amazon.com, but to display and perform on Google Shopping as well.