NEW YORK (CNNMoney) -- President Obama announced new limits on how much "metadata" the National Security Agency can collect about Americans' telephone conversations.
OK. But what's the metadata he's talking about?
It's information wireless carriers collect about where, when and to whom customers make phone calls. It doesn't include any recordings of the actual phone call itself.
The metadata can contain phone numbers, the time and duration of calls and the location of the caller and the recipient.
But it also goes beyond that: It can include which cellular towers were used to transmit the call and what kind of phone was being used.
When bundled together, those metadata can potentially reveal a whole lot about a caller.
For example, knowing that a person was calling someone frequently in the early hours of the morning could indicate that they have a close relationship. Knowing that the call rapidly switched cell towers could indicate that the caller was driving during a call.
Currently, the government collects and stores most of those records.
Obama isn't proposing that the NSA stop collecting metadata entirely. But the scope will be more limited. Fewer calls will be cataloged, and the government will have to get a judge's approval to tap the records.
Eventually, Obama said the government will stop gathering and keeping metadata, but there is no plan yet to replace the existing system.