Android developers have opportunities to earn revenue from mobile advertising. AdMob data shows that Android traffic grew significantly from November 2009 to April 2010, though it remains smaller than iPhone traffic. The top Android handset brands are Nokia, HTC, and Samsung. Most Android devices run version 1.5 or 2.1 of the OS. Developers can use AdWhirl to integrate multiple mobile ad networks, maximize fill rates and revenues, and centrally manage monetization across iPhone and Android apps.