DEFINITION of Y2K
Y2K is the shorthand term for "the year 2000" commonly used to refer to a widespread computer programming shortcut that was expected to cause extensive havoc as the year changed from 1999 to 2000. Instead of allowing four digits for the year, many computer programs only allowed two digits (e.g., 99 instead of 1999). As a result, there was immense panic that computers would be unable to operate when the date descended from "99" to "00".
BREAKING DOWN Y2K
While there were a few minor issues once January 1, 2000, arrived, there were no massive malfunctions. Some people attribute the smooth transition to the major efforts undertaken by businesses and government organizations to correct the Y2K bug in advance. Others say that the problem was overstated to begin with and wouldn't have caused significant problems no matter what.
At the time, which was the early days of the internet, the Y2K scare or Millennium bug as it was also called, had many plausible reasons for concern. For instance, for much of financial history, financial institutions have not generally been considered cutting edge tech-wise. Knowing most big banks ran on dated computers and technologies, it wasn't irrational for depositors to worry the Y2K issue would seize the banking system up, thereby preventing people from withdrawing money or engaging in important transactions. Extended to a global scale, these worries of an epidemic like panic had international markets holding their breath heading into the turn of the century.
Interestingly, the episode came and went with little fanfare — with it now a fun and quirky side note to the early days of the internet.