Small and mid-size ecommerce retailers experienced a lag in sales this past April, but prospects brightened considerably in May, according to a new report from Dydacomp.

In April, web sales declined by 4.3 percent, but they shot back up by 8.6 percent in May. Dydacomp CEO Fred Lizza was quick to note that this marked the single largest year-over-year growth rate, both for gross sales and number of orders. The size of the average order was up 1.8 percent, while total growth in the volume of orders increased by 6.7 percent in May.

"Books continue to be a high-growth category despite the dominance of Amazon.com and the popularity of e-readers, recording a 22 percent year-over-year increase in total sales in May," Lizza says. "We believe this growth is influenced by many religiously affiliated organizations that publish unique content not available through mainstream distribution channels."

Separate data from comScore has noted the growing popularity of online shopping. During the first quarter of 2012 alone, ecommerce sales were up year-over-year by double-digits.