The mobile-optimized +1 button made its debut on select Android and iPhone browsers Thursday.
"The button will automatically be visible to anyone on Android 2.1+ and iOS 4.0+ browsers," Punit Soni, lead product manager for Google+ Games and Mobile, wrote in a post on Google+. "When you +1 something, it will be displayed publicly across the Web as an annotation on the content you +1’d."
The +1 button mobile upgrade follows recent feature rollouts, including friend annotations, +1 sharing with Google+ circles and +snippets.