If you're wondering what TL;DR would mean on the internet. Here's a brief explanation -- TL;DR stands for too long, didn't read. If you come across an article or post that gets a bit too long, you can use the TL;DR abbreviation to let other people know it was too long. On sites like Reddit where it is popular it's used mainly at the end of long posts where the author also adds a brief explanation for people not wanting to read their long posts.