comScore today officially unveiled a new measurement tool called Media Metrix Multi-Platform that combines and compares U.S. desktop, Android and iOS usage for the big properties in the country.
Among the top 10 companies on this list, both Apple and Amazon had the largest percentage of mobile-only (smartphone or tablet) users in comparison with their entire digital reach. Nearly 35 percent of U.S. visitors to Apple properties and 22 percent of Amazon traffic came strictly through mobile.
Compare that to Microsoft, who had just over 5 percent of its users accessing its content via mobile-only. Important to note that comScore’s mobile numbers reflect iOS and Android users only.
The average company in the Top 100 grew its reach by an average of 38 percent when adding mobile-only users statistics. The biggest movers were Groupon (up 223%), Zynga (111%) and Pandora (183%).
comScore will update the new rankings every month. Check out the full list here.
Previously on GeekWire: Smartphone market share: Apple gains ground on Android
Reach staff reporter Taylor Soper at email@example.com or on Twitter @Taylor_Soper