system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: what is Millennials ?
gpt
We tend to refer to a whole generation of people by a name, because their fashion and internet memes / fads change from generation to generation.

Millennials are people born in the 1980's and 90's; unlike previous generations, they grew up with computers and internet and phones, and are quite active with social media.  They were also just about out of college when the recession of 2001 hit the computer industry and caused a lot of them to be unable to get jobs.