Photos: Instagram
Co-founded by Kevin Systrom and Mike Krieger, Instagram is a free iOS app that lets users take photos, give them a retro look with a number of image filters and then share them through Facebook, Twitter, Foursquare or Tumblr.

Since its launch last October, Instagram has become a popular tool for iPhone users. The six-man team reports 10 million users have added 150 million plus photos. To celebrate, Instagram launched version 2.0 with a neater interface, more filters and performance of up to 200 times faster.

Last updated September 26 2011: 12:05 PM ET
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