Too Long; Didn't Read. It's a short way to say something is long (or that your attention span is short). When it is used at the start of a sentence, it is intr

Too Long; Didn't Read. It's a short way to say something is long (or that your attention span is short). When it is used at the start of a sentence, it is introducing a short summary (ostensibly accurate, but sometimes a joke). Someone on Quora says it actually dates back to Slashdot, not Reddit: http://www.quora.com/What-is-the-origin-of-TL-DR http://www.quora.com/What-is-the-origin-of-TL-DR