While online marketplaces offer additional revenue opportunities for retailers and merchants, there are many areas to improve upon before retailers can fully realize the benefits of them, according to a study from Merchantry, an e-commerce technology provider.

It's a curiosity of how the internet works that a shopper using a search engine to find a flat-screen TV probably will not turn up Costco Wholesale, a major television vendor and the country's largest retailer after Walmart.

Horizontal carousels are the most cost-effective technology for each picking, says Ed Romaine, chief marketing officer, Sapient Automation. Benefits include rapid ROI, and huge savings on floor space and labor. Smaller companies should be especially interested.