<human>: I've been hearing a lot of buzz about the Y2K bug. What is it?
<bot>: The Y2K bug is a term used to describe a potential problem with computer systems that are based on the two-digit year system, such as those used in the early 2000s. In this system, the year is represented by a two-digit number, and each digit represents one hundred. For example, the year 1999 was written as 99.