TL;DR is internet slag for Too long; didn't read, and indicates that something would take too long to read.
Too long; didn't read (TL;DR)
Internet slag used when something would take too long to read so the user didn't.
Internet slag used when something would take too long to read so the user didn't.
TL;DR is internet slag for Too long; didn't read, and indicates that something would take too long to read.