1) the phrase lazy trolls use when they have nothing to say in response
2) a phrase used when a post REALLY IS long, pointless, and repetitive, and should barely be read... but most of the time people do anyway
3) a lie
Person A: -long post about how furries aren't bad people- and that is why furries aren't bad people...
Person B: tl;dr
Person A: troll...
Person C: -long, overly repetitive post, by a furry (the bad kind)- AND THAT'S WHY FURRIES ARE TEH AWESHUMNESS, AND YOU ARE GUILTY OF FURSECUTION
Person D: tl;dr, dude I never even insulted you guys in the first place
Person C: -rages-