Customers responding to email marketing and shoppers navigating directly to online stores (including app traffic) accounted for the highest share of purchases on phones in the first quarter of 2014, according to a recent report from Custora.

Email marketing generated 26.7% of retail purchases made on phones in 1Q14, compared with only 20.9% of sales on desktops and 23.1% on tablets.

Direct traffic also drove a larger share of purchases on mobile phones compared with desktop, with one-third (32.9%) of sales coming from shoppers who went straight to online stores/apps.

On tablets, paid search was the leading marketing channel in 1Q14, driving 24.8% of sales.

Below, additional key findings from the report, which was based on US e-commerce data from over 100 retailers, 70 million consumers, and $10B in transaction revenue.

E-Commerce by Device

In the past four years, the percentage of traffic to e-commerce sites from mobile devices (phones and tablets) jumped from 3.4% to 36.9%.

Conversion Rate

The average conversion rate and average order value on e-commerce sites in 1Q14 was markedly lower on mobile phones than on desktop computers. Both were also lower on tablets than on desktop computers, but the difference was significantly less.

Time Spent

Consumers spent the most time on e-commerce sites when accessing via desktop computers (3:39 minutes on average); tablet users spent a little less time on site on average (3:16); and consumers using their phones spent the least amount of time on site (2:13).

About the research: The report was based on 1Q14 US e-commerce data from over 100 retailers, 70 million consumers, and $10B in transaction revenue.