Here on HN, you occasionally find tl;dr near the top of a comment thread -- but it's followed by a nice summary of the article. Instead of expressing the rather worthless sentiment of "I didn't read this", it's expressing the far more valuable "if you're not sure you want to invest the time in reading this, here are the highlights of what you would have otherwise missed."

Speak for yourself.

I'll often read the comments briefly first before deciding if I want to read an article.