Nearly two-fifths of respondents—39.7%—to a new Internet Retailer survey plan to take part in the Google Shopping  program. It is replacing the free clicks on Google Product Search with paid clicks designed to attract online comparison shoppers.

The June survey, which focused on search marketing, drew 128 responses. Complete findings will appear in the August issue of Internet Retailer magazine.

Of the respondents, 29.4% have yet to decide whether to take part in Google Shopping, while 23.0% said they would opt out of the program. The remainder, 7.9%, said they do not know what Google Shopping is.

Google has said that the new program, scheduled to be in place as online consumers are starting to shop for holiday gifts this fall, will give retailers more control over where their products appear in Google. That’s because instead of bidding on keywords for paid search ads, retailers will bid on the amount they will pay if their product listings in search results attract clicks or result in sales. Google Shopping will replace the Google Product Search comparison shopping service’s free listings.

That more than a third of respondents are either unsure about taking part, or had yet to hear of Google Shopping, suggests that Google has some marketing of its own to do. But the largest e-retailers are ready, says Aaron Goldman, chief marketing officer of online marketing software firm Kenshoo Ltd.. Those retailers are working to integrate Google Shopping with other online marketing programs.

“Kenshoo works with seven of the world’s 10 largest retailers and they are definitely up to speed on Google Shopping,” he says. “Key challenges include collaboration between the paid search and feed management teams, definition of ‘product targets,’ and ongoing management and optimization of increasingly large and sophisticated product ad campaigns.”