Facebook agreed to buy Instagram in April and the deal closed early last month, shortly after gaining .

Instagram's surge in mobile growth over the past six months doesn't mean that Twitter is struggling, Kerravala said. It means simply that right now, users are more interested in photos than text.

"Well, they're focused on photos and the visual element, which is very popular these days," he added. "I think Instagram is easier to use for most people. It's visually centric."

Sharon Gaudin covers the Internet and Web 2.0, emerging technologies, and desktop and laptop chips for Computerworld. Follow Sharon on Twitter at , or subscribe to . Her e-mail address is .

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