Apps for live streaming video from mobile devices have been around for a while but early attempts weren't too user friendly. Only recently has the topic received wider media coverage with the launch of the Meerkat app. Now Twitter has launched a direct rival to Meerkat, called Periscope. 

Periscope is currently available for iOS devices only but the team says it is working on an Android version of the app as well. Periscope users can follow each other, and are automatically notified when a contact goes on air. That said, broadcasts can be limited to a select group of people if you prefer. Viewers can send comments and "hearts" to interact with the broadcaster. You can also configure the app to tweet a web link to your broadcast and broadcasters can choose to make their content available for replay for 24 hours after the original transmission. 

Periscope is optimized for for iPhone 5, iPhone 6, and iPhone 6 Plus and requires iOS 7.1 or later. It can be downloaded and installed now for free from the Apple App Store