• by Laurie Sullivan  @lauriesullivan, July 15, 2015

Google's Purchase on Google might make it easier for consumers to buy products directly from mobile search adsin Google Shopping, but merchants will still handle the actual transaction through partnerships.

One transaction integration partner, CommerceHub, announce Wednesday it will support a clickable feature on the merchant-branded product pages in Google Shopping through product listing ads. The two companies have been working closely to make purchasing easier while merchants keep control of their customer data.

While more than 50% of searches on google.com occur on mobile devices, mobile shopping converts at one-third the rate of desktop and tablet, according to Google. As smartphones become the prevailing consumer-shopping device, this mobile conversion gap creates a major issue for retail advertisers looking to grow sales.

The big companies that will drive these sales do not sell on Amazon, said CommerceHub CEO Frank Poore. The retailers want to participate, but it's a challenge to make these order integration possible, he said. 

A "Buy" button will appear in some promoted mobile search results, taking consumers to a page where they can buy the advertised product. It's part of a strategy to keep merchants with Google Shopping and consumers having the ability to make a purchase with one click.

Google Product Listing Ad click volume rose 30% year over year (YoY), as PLAs produced 32% of Google paid search clicks for retailers, up from 25% in the year-ago quarter, according to aggregate Merkle RKG client data.

Among non-brand traffic, PLA click share was 57% in Q2 2015, up eight points from a year earlier. While the return on investment is higher for PLAs than text ads, the average order value remains consistently lower, which Merkle RKG analysts think could change with the Purchase on Google feature. The click-through rate advantage PLAs hold over text ads has declined as Google has devoted fewer impressions to text ads, which drove up text ad CTRs.

Google needs a way to encourage retailers to stay with the engine, rather than jump to Facebook or other social sites driving consumers to merchants. Facebook produced nearly 60% of social media-driven site visits in Q2 2015, up from 51% in Q2 2014. Pinterest generated 18% of social site visits on average in Q2, but often produced a higher share for retailers making concerted efforts on the site, according to Merkle RKG.