• by Sarah Mahoney  @mahoney_sarah, April 24, 2015

A new report from Forrester Research says that online spending in the U.S. will hit $334 billion this year, or about 10% of all sales. Transactions on mobile devices account for 10% of the e-commerce total, and the two largest categories — apparel and accessories at $48 billion, and consumer electronics at $30 billion — now account for more than one-quarter of online sales.

The forecast puts e-commerce on track to increase by some 10% per year for the next five years, totaling $480 billion by 2019. 

With 69% of the population making purchases online, “shoppers are distributing their spend across a variety of categories,” writes Sucharita Mulpuru, its VP and principal analyst for e-business. “In the year 2000, three categories — computers, clothing, books — dominated 46% of online retail, while today consumer electronics makes the list alongside computers and clothing.” Grocery and home improvement purchases remain stubbornly resistant, and are the least penetrated of the 30 categories that Forrester tracks. 

But with online research influencing something like $1 trillion in sales, there are major opportunities for other segments that have trailed in the online arena, such as furniture and auto part sales, both of which are growing faster than e-commerce overall.

The slowest growth rates, however, are in categories that are already digitally driven. “By 2016, more than 50% of revenue in the books, music, and software categories (including digital distribution) will happen online,” she says, and by 2019, she forecasts that 96% of all music sales will occur online, as well as 82% for software.

As the market matures, “a number of retailers are significantly outpacing the industry average growth rate and stealing market share from less innovative and slower-moving web retailers.”

The ones most likely to emerge as winners? Those that are optimizing their mobile presence, matching aggressive shipping offers, making sure they are protected from data breaches, and improving their omni-channel capabilities.

Separately, Amazon says its sales gained 15% in the first quarter, to $22.72 billion, compared with $19.74 billion in the same period a year ago. Excluding the impact of foreign exchange rates, net sales climbed 22%. And it predicts second-quarter sales of between $20.6 billion and $22.8 billion, up between 7% and 18% compared with the second quarter last year.