Khatib decided to share a longstanding problem in AIDS research in the form of Foldit, a program that reframes scientific challenges as a competitive multiplayer computer game.

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Social investors share a different problem: They and their intermediaries have a hard time finding investees, because too many social entrepreneurs remain dependent on unreliable income sources and are unable to return funds with interest, or have strategies that may not benefit from investments (more on the dangerous promise of impact investments).

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Badoo has already achieved the critical mass needed to make it a going concern and seems to have no problem persuading users to share personal details -- a fact that should be encouraging to Highlight and other, newer social startups.

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