Internet radio service provider Pandora today announced that it has hit a significant milestone, signing up over 200 million users in the United States to date.

Notably, half of those – or 100 million registered users for those equally bad at math as myself – were added in less than two years, while the company’s been around for almost eight years now.

Roughly 70 million of its users are ‘monthly active listeners’.

Pandora founder Tim Westergren said:

“We started this company to help people discover and enjoy music they love, and to help artists reach and grow their audiences. Only in our wildest dreams did we imagine what it would become.

It is now clear that radio is changing, and that’s great news for music fans and for the tens of thousands of working artists who now have a home on the air.”

The publicly-listed company has released more stats to celebrate:

- Pandora streams 200 million songs before 10 AM every day
- Listeners have personalized their stations with more than 25 billion ‘thumbs’
- Last month, Pandora played more than 100,000 unique artists and more than 1 million unique songs
- More than 140 million listeners have tuned in to Pandora on a mobile device

Earlier this month, Pandora shared its latest monthly audience metrics, revealing that listener hours for Pandora during March 2013 were just south of 1.5 billion, an impressive increase of 40 percent from 1.07 billion during the same period last year.

Pandora’s share of total radio listening in the United States was a little over 8 percent in the month of March 2013.

In the same month, CEO Joe Kennedy announced plans to step down from his role at the company, right after Pandora reported strong financial Q4 results, including revenue of $125 million for the quarter.

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Pandora slaps a 40 hour/month limit on free mobile listening, says less than 4% of users affected

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