To Twitter, the reasoning is simple: the company is devoted to "social justice," and that's not possible when officials are using these public data sets to track protesters, scoop up people's names and otherwise curb freedom of expression.

The policy and resulting crackdown isn't going to stop authorities from collecting information through other means, whether it's old-fashioned searching or formal requests. However, it'll at least make the process harder. Agencies will have to really want that information to get it, and can't just gather it en masse with a simple program.