TL;DR Means Too Long; Didn't Read
TL;DR is just lazy people being too lazy to even write out that they didn't read something. What's your problem? Sit down and read something, yeesh! TL;DR basically sums up the biggest problem with this generation: awful attention spans. No one is willing to sit down and really absorb a meaningful essay or article, let alone a serious book.
If you think something is worth reading, read it, but don't not read it because you're lazy. Then you'll become stupid, like this guy.