"Too long; didn't read." An insulting acronym that is usually the entire content of a comment on a lengthy blog or bulletin board post.
Sometimes the presence of a tl;dr is hilariously deflating, collapsing all of the commenter's contempt for a blowhard's pseudo-philosophical claptrap into into five characters. It's the equivalent of interrupting a passionate but misguided hour-long speech at some formal occasion with a one-armed shrug, and then walking away without even partaking of refreshments.
(It's even funnier when the original poster doesn't know what the acronym stands for. Clueless posters often need to have the insult explained to them -- publically -- which provides a free chance for a second commenter to repeat it.)
Of course, tl;dr is often used by trolls to irritate the authors of thoughtful, carefully-written posts about politics or other important topics. For every blowhard that is taken down a notch by a wittily-placed tl;dr, there is a serious blogger for whom hours of research are dismissed with one.
Anil Dash, in a typically comprehensive misunderstanding of the way Internet culture works, takes this to mean that the acronym
epitomizes the short-attention-span crowd, the willfully idiotic segment of the online population that 1. we all sometimes belong to and that 2. makes for the shittiest experiences on the web.
This may have been true five years ago -- I don't know how long the acronym has been around -- but I doubt it's true anywhere any more. Like so many other Internetisms, tl;dr is too deeply embedded in irony to mean simply what it "stands for." Nobody seeing a tl;dr (with the exception, perhaps, of Anil Dash) thinks that the commenter honestly believed that it was useful to inform the original poster that the essay was boring. Trolls skate on one edge of the irony ("I reject your intelligent contribution to this forum!") while clever commenters skate on the opposite ("Your crap is so far beneath me that I'm not even going to write out a full word to tell you how crappy it is!"), but I suspect it's been a long time since anyone's been on a forum where tl;dr simply stood for "too long; didn't read."
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