One thing the Bush administration says it can do with this meta-data is to start tapping your calls and listening in, without getting a warrant from anyone. Having listened in on your calls, the administration asserts that if it doesn't like what it hears, it has the authority to detain you indefinitely without trial or charges, torture you until you confess or implicate others, extradite you to a Third World country to be tortured, ship you to a secret prison facility in Eastern Europe, or all of the above. If, having kidnapped and tortured you, the administration determines you were innocent after all, you'll be dumped without papers somewhere in Albania left to fend for yourself.-matt yglesias

pretty much hits the nail right on the head.