"What you care about is the metadata, because metadata does not lie. People lie on phone calls when they're involved in real criminal activity. They use code words, they talk around it. You can't trust what you're hearing, but you can trust the metadata. That's the reason metadata's often more intrusive."

Yes, telcos have traditionally retained phone records for billing purposes, but they usually don't store it beyond the billing cycle, given the costs of storing so much data.Also, metadata goes much further beyond who you called and for how long. Tony Abbott and George Brandis have likened the proposed regime to the seemingly innocuous analogy of reading the details on an envelope (the metadata), but not the letter itself (the content). But, in reality, the metadata of a phonecall can reveal far more, than what was actually said during the call. As high-profile US whistleblower Edward Snowden puts it:Retaining metadata means agencies can accumulate a record of everyone you have called, everyone they have called, how long you spoke for, the order of the calls, and where you were when you made the call, to build a profile that says far more about you than any solitary overheard phone call or email.It can reveal not just straightforward details such as your friends and acquaintances, but also if you have medical issues, your financial interests, what you're buying, if you're having an affair or ended a relationship. Combined with other publicly available information, having a full set of metadata on an individual will tell you far more than much of their content data ever will.The General Counsel for the United States National Security Agency has publicly stated, "metadata absolutely tells you everything about somebody's life. If you have enough metadata, you don't really need content". According to the former head of the NSA, Michael Hayden, the US kills people based on metadata.