5:25 PM -- Video calling will be in use by 29 million people around the world by 2015, according to a study from Juniper Research Ltd. The uptick is due in large part to Apple Inc. (Nasdaq: AAPL)'s introduction of FaceTime on the iPhone 4, but it won't lead to video calls becoming a mass-market tech in the next five years, the analyst house says. Roadblocks like a lack of interoperability, 3G restrictions, and capable handsets may hold it back.

Barclays Capital analyst Ben Reitzes takes a more bullish approach. He wrote in a note today that he expects FaceTime to be enabled on all Apple devices over time. Specifically, he predicts there will be 150 million FaceTime-enabled devices by 2012, including iPhones, iPods, and iPads. Down the road, some non-Apple devices also may get FaceTime, as it's an open standard.

FaceTime is still restricted to WiFi, but it isn't the only video-calling app out there. fringland Ltd. 's app works on 3G, as does Qik Inc. 's, a contender for Light Reading's Leading Lights Best New Mobile App, on the High Tech Computer Corp. (HTC) (Taiwan: 2498) Evo. (See Fring Punches AT&T in the FaceTime, Leading Lights: Mobile Services/Apps Finalists, and Video Chat: Meet the New Data Hog.)

Yahoo Inc. (Nasdaq: YHOO) also announced last week at CTIA that video calling would be enabled on its Messenger App for iPhone.

Juniper analyst Anthony Cox notes in the report that video calling has seen false dawns before, but if this new tide of apps comes to 3G, it could really just be the calm before the storm. — Sarah Reedy, Senior Reporter, Light Reading Mobile