Twitter's Periscope gains 1 million users in first 10 days

One million users signed into Twitter's new live streaming app Periscope in the first 10 days after its launch, according to TechCrunch. That's a fast clip for a new social network, but can its momentum continue?

The challenge facing Periscope isn't user interest or support from its parent, Twitter.

It may come down to usage and speed.

Periscope app
Source: Periscope
Periscope app

If a user is on a data connection, streaming video can rack up data costs on wireless phone bills.

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The bandwidth risk is on the consumer side, says one tech expert.

"A few hours of streaming a week and they'll easily blow through their mobile data plan limits. The sticker shock could end up curbing usage in a blink of an eye," said Lou Basenese, founder of Disruptive Research.

The app is still not yet available to Android users.

Disclosure: CNBC's parent company, Comcast, is an investor in Meerkat, a rival of Periscope.