Twitter is public, but it could offer a lot more privacy

Yesterday, Twitter issued a call for proposals to measure its “contribution to the overall health of the public conversation” so that it could help “encourage more healthy debate, conversations, and critical thinking,” and discourage “abuse, spam and manipulation.” It’s the kind of high-minded request that you’d expect from a platform that presents itself as a powerful civic forum for the digital age. But measuring the “public conversation&r