Even as Internet companies such as Zynga Inc. and Groupon Inc. file to go public, Twitter Inc. is taking a different route: It is continuing to tap private investors.

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The CIT allows Mr Emanuel to tap the private sector for money, rather than just raising taxes and borrowing.

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It's less likely the government will be able to tap into private databases anytime soon, but it's still a cause for concern down the line, privacy advocates say.

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