TLDR is a pragmatic device; it's a written discourse marker. Calling it "unnecessary" is just like saying that "well...", "y'know", "so...", "like" and all those other little "filler words" that your high school English teacher doesn't like are "unnecessary". In formal prose, where all that's supposed to matter is textual semantics, sure, they're not necessary, and I wouldn't use them there. But in informal discourse, they're essential; not for conveying propositional information, but for negotiating social discourse information.
The "TLDR" is all-caps, so it grabs your eye out of the wall-o-text that you may be skimming over, and says "hey here is my basic point". And maybe then you'll go "hey that's an interesting point" and scroll back up and read their lengthy argument, story, or whatever, in all its labrynthine discoursiveness.
And now to demonstrate it I will include some lorem ipsum. Hipster Ipsum, to be precise. Swag polaroid tempor iphone echo park ethnic 8-bit, cosby sweater beard semiotics in. Magna organic neutra, exercitation laborum quis jean shorts aliqua ex eiusmod gluten-free pitchfork butcher. Cosby sweater disrupt keytar qui, beard pariatur lo-fi sustainable magna skateboard sint farm-to-table umami. Intelligentsia pour-over flexitarian, banh mi meh ad meggings thundercats ex. Labore tofu aliquip officia kale chips, bushwick single-origin coffee. Quinoa laborum velit 3 wolf moon placeat eiusmod, nisi brooklyn cred VHS stumptown. Gastropub try-hard intelligentsia, fashion axe 3 wolf moon wes anderson actually officia proident laboris american apparel do.
High life pitchfork ad tousled wolf, fugiat gentrify put a bird on it keytar nesciunt beard aliqua jean shorts post-ironic laboris. Flexitarian vice aliquip pork belly non, anim commodo eu. Dreamcatcher nulla cred, echo park church-key retro sint neutra vice mustache. Vero deep v art party, blog organic bicycle rights labore pinterest wayfarers polaroid quinoa jean shorts vice. Ad banh mi authentic art party. Trust fund et banjo bespoke portland. Cardigan disrupt american apparel aliquip kale chips non.
Craft beer vero cosby sweater kale chips ex nihil cardigan, truffaut authentic photo booth sed. Irony ethnic keytar post-ironic, ugh enim tonx truffaut before they sold out. Kale chips tattooed terry richardson keytar marfa carles artisan, sunt flexitarian vice ex. Umami sapiente direct trade etsy ut, hoodie readymade jean shorts brooklyn VHS cray polaroid. Anim pork belly swag minim. Master cleanse narwhal cred pinterest. You probably haven't heard of them wes anderson est, high life truffaut culpa stumptown ethical williamsburg vero sapiente.
Etsy plaid irony, brooklyn post-ironic williamsburg dolor butcher master cleanse pariatur aliqua next level cred. Seitan aliquip qui disrupt lomo literally. Sapiente tumblr laborum, gastropub bicycle rights non post-ironic pug ut. Do nisi narwhal, ad odio before they sold out disrupt brunch tumblr polaroid dolore +1 odd future. Viral officia readymade, plaid forage assumenda post-ironic cupidatat you probably haven't heard of them portland sint qui. Cardigan try-hard portland id selfies four loko, assumenda ethical letterpress aesthetic. Neutra non art party locavore aesthetic, actually freegan tonx cardigan godard ex gentrify.
TL;DR: One sentence with a block of all-caps beginning it sure catches your eye at the end of a long post.
That was completely unnerving. Without even realising I had done it I completely skipped over the block of text to the TL;DR and only after did I realise it was just Lorem Ipsum nonsense.
I totally agree with TL;DR usage, it's a modern device for modern internet communication. People continue to use it because it's useful and works, not because they have an agenda to ruin the english language or are semi-illiterate. Possibly my favourite thing about it though is its lack of pronounceability. Its entirely invented and used as a written construct and is actually quite cumbersome to try to say out loud.
Interesting tangent, as someone who was fluent in Latin many moons ago (could speak it at an English conversational pace), I literally had to force myself to ignore your filler (which includes several Latin fragments).
It's from a "Hipster Ipsum" generator. Designers traditionally use a piece of malformed Latin to indicate "there is some text here" without having actual text.
What if TL;DR is not in all-caps, e.g. tl;dr? The lowercase version is quite prevalent on Reddit. Of course it still stands out from a block of standard English prose because of the odd shape of the combination (especially the semicolon in the middle), but not so much as the all-caps version.
