tl:dr stands for "too long; didn't read"

There's a new short form on the internets: tl;dr.

It means "too long;didn't read". I love it! I want to use it at work - after someone writes a really long email message. I just want to reply "tl;dr".

Then when they respond to that with a, "I'm sorry I didn't understand," my next response will be "too long; didn't read".

I think it's great that you're not allowed to be long-winded on the internet. Too long; didn't read. Perfect. We simply don't have the time or desire to read much - UNLESS we're considering spending a lot of money on something. Then we want to read a lot about it before we make our purchase.

A lot of people on message sites like "reddit" post a long answer or discussion and then, at the end, type "tl;dr:" and write a short, one-sentence summary of what they just said. For all the people who don't read long posts.

In the business world this is called "Executive Summary".