• by Gavin O'Malley , August 10, 2012

While online ad growth remains a concern, ecommerce continues to boom, according to the latest estimates from comScore.

Domestically, online retail spending reached $43.2 billion in the second quarter of the year -- up 15% year-over-year, comScore reports.

This represents the eleventh consecutive quarter of positive year-over-year growth and the seventh consecutive quarter of double-digit growth, comScore Chairman Gian Fulgoni noted Friday.

“While the second quarter’s 15-percent growth rate couldn’t quite match the especially high growth rate from the first quarter, it was nevertheless almost four times higher than the growth in overall consumer spending, a sign of continued strength in the e-commerce channel,” Fulgoni said.

That said, while e-commerce remains strong, comScore is taking a cautious view of the second half of the year in light of renewed signs of economic uncertainty, along with a stubbornly high unemployment rate.

In fact, consumer perception of the economy has recently deteriorated, with 56% now viewing economic conditions as poor -- up from a level of 49% three months ago, Fulgoni pointed out.

“So, even as commerce increasingly shifts to the online channel, any significant future pullback in overall consumer spending could dampen the strong double-digit growth rates we’ve been experiencing for the year-to-date,” he added.

During the quarter, the top-performing online product categories included digital content and subscriptions; consumer electronics; flowers, greeting sand gifts; computer hardware; and apparel and accessories. Each of these categories grew at least 16% year-over-year.

Also of note, 42% of e-commerce transactions included free shipping, representing a seasonal pullback from 52% during the fourth quarter of last year.