More than a third (37%) of US and UK retailers and branded manufacturers have annual revenue of US$15 million or more exclusively in online sales, and approximately 40% of their total annual revenue from all sales exceeds US$29 million, and 74% also have a bricks-and-mortar location, according to the '2015 Online Retail Survey' from cloud-based e-commerce solutions firm ChannelAdvisor, which identified new trends, opportunities and challenges in the e-commerce space. This article is copyright 2015 The Best Customer Guide.

The study found that Amazon generates the greatest sales volume for 60% of respondents when comparing marketplaces, and more than half of retailers use FBA to streamline logistics and reach more Amazon Prime subscribers.

More than a third (35%) of retailers listed Amazon Product Ads and Amazon Sponsored Links as the digital marketing channel that provides the most return on investment (ROI).

"The results of the survey signify the rapid growth of Amazon's third-party marketplace," said Scot Wingo, ChannelAdvisor executive chairman. "Amazon's three-pronged approach that focuses on selection, value and convenience has clearly benefited merchants as well as online shoppers, and it's helped position the company as a leader in e-commerce."

More than a third (34%) of U.S. retailers are seeing 21 to 30% of their web traffic come from mobile devices, whereas a third of U.K. retailers are seeing 11 to 20% of their web traffic come from mobile

Nearly 90% of retailers currently have a presence on Facebook, and Facebook is the social platform that creates the most sales conversions for retailers' products. Nearly a quarter (23%) of retailers said Facebook provides the most ROI for their company when comparing the performance of various digital marketing channels.

Same-day delivery is offered by more than a quarter of retailers (28%), while nearly two thirds (63%) of retailers offer next-day delivery to customers, and more than half (56%) of retailers offer two-day shipping. Nearly a third (32%) of retailers offer international delivery, and click-and-collect is offered by 14% of retailers.