A database containing the personal information of 56 million US residents, from names to addresses to phone number and ages, were found on the internet. That is not the worst of it, it has been seen that this database is being housed from a computer with a Chinese IP address. An IP address is, in simple terms, a label that is used to identify a device on a computer network, such as the internet. It is a destination address of sorts that lets computer traffic know where to route information.
This database is from Checkpeople.com, which is a people-finder website. For a fee, you can enter someone's name, and it will look up their current and past addresses, phone numbers, email addresses, names of relatives, and even criminal records in some cases, all presumably gathered from public records. It is information that not only was sitting for anyone to access, without the fee, but it was also sitting in the hands of presumably foreign adversaries.
The discovery of this open database was told to the media by a white-hacker operating under the handle Lynx. By itself, this data could be seen as harmless since all of this information was already public record - anyone could find it with some basic google searched. But bundled together with other stolen information, this could be worth a lot of money to some people wanting to do harm by combining data assets. The person who disclosed this vulnerability, and the media outlet The Register who first reported it, has been unable to reach CheckPeople to alert them to the leak.
This is just an illustration of how this sort of personal information is already currently in circulation and why personal security should be taken seriously by everyone. Leaving security to the experts will not protect you alone anymore.