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Facebook Holds Its Fourth f8 Developer Conference

SAN FRANCISCO, CA - SEPTEMBER 22: Spotify CEO Daniel Ek makes an appearance during a keynote address by Facebook CEO Mark Zuckerberg at the Facebook f8 conference on September 22, 2011 in San Francisco, California. Facebook CEO Mark Zuckerberg kicked off the conference introducing a Timeline feature to the popular social network. (Photo by Justin Sullivan/Getty Images)

Spotify

Streaming service Spotify is adding "Private Listening" mode. CEO Daniel Ek announced via Twitter, “We’re rolling out a new client as we speak where you can temporarily hide your guilty pleasures. It works like a browser’s private mode.” (Sept. 29)