In keeping with nerdy computer abbreviations Y2K is a short form of year2000, where K represents a thousand. The Y2K bug is a problem that stems from the use of a two digit representation of the year (i.e 99 instead of 1999) in the early days of computing, when machines could handle very small data and memory was expensive. Therefore engineers and scientists choose date representation as ddmmyy and not ddmmyyyy. What does it do to you is the question that arises. Like if i turn 19 next year the computer is going to show -18. And i will be born in 2018 !