Too long; didn't read. More colloquially expressed as "tl;dr."
Have you ever encountered this expression in the wild? If so, that 'wild' is certain to have been a digital one. This expression, used mainly within internet forums and online comment sections, indicates that the comment or forum post which came before is of such a great length (oftentimes no more than a few sentences) that the person using the term isn't even going to bother to read what is written. It usually seems to carry an undercurrent of purposeful dismissiveness - 'Thanks for sharing your thoughts. I don't care what they are.' It's also, quite unfortunately for writers, a very common attitude.
Consider a stranger who doesn't know the difference between you and the random people at the grocery store they wish would stay out of their way while they reach for Pringles. This stranger is, if you're lucky, willing to invest perhaps five seconds into reading what you might have to say. The average person won't spend more than a handful of extremely guarded and distrustful moments reading something written by someone they do not know and have no pre-vested interest in.
This, though sad, is a fact.
The writer's task, in this modern 'tl;dr' era, is the same as it ever was. As Kurt Vonnegut said, a writer 'must use the time of a total stranger in such a way that he or she will not feel that time was wasted.' This quote can be looked at in the light of two truths:
1. Strangers are inherently unwilling to spend their time reading writing by writers unknown to them
2. Once a stranger decides to entrust you with their time, that trust has to be immediately and continually earned.
Ensuring that you fulfill the standards of the second of these two attributes is a prerequisite for writing which engages the reader, and by skillfully obviating the first of these attributes, writing can get a foot in each of the three successive doors blocking one from converting an uninvested reader into an invested reader. These three doors are:
1. Trust - The first door writing needs to unlock in the reader is the door to their trust. The reader needs to be able to trust, from the very beginning, that the writing is both going somewhere and is technically executed at least to the standards of their minimum acceptance level. This level is different for each reader, but the best option for the writer is to ensure that their own standards for writing are of greater than average acceptability.
2. Mind - The second door leads to the mind of the reader. If a piece of writing can get its foot in the first door, it then needs to quickly establish some link between its content and the reader's thoughts. If a piece of writing can produce empathy, understanding, and - most importantly - identification at an early point, it will contain resonance and immediacy for the reader. These are the lubricants to the hinges of the third door.
3. Imagination - If one is so fortunate to have opened a reader's third door, their writing would have unsealed the innermost realm of the reader's sense of reality and self. Just as it sounds, this is not a thing done lightly. The effect of good writing in combination with a reader's imagination is a magical thing indeed. Respect the capacity for imagination that lies within all of humankind. The purpose of good writing isn't to show off one's own imagination, but to kindle the imagination of the reader.
If something in your writing can touch a reader's memories in an uncanny way, or show them a highly-focused aspect of human nature in a manner that hums with resonance for them, that is an experience that a reader will appreciate. If a piece of writing can produce this effect consistently or even sporadically, people will be grateful for this relatively rare experience.
Going back to our earlier parlance, writing that makes consistent sojourns through the reader's third, imaginative door will maintain your reader's trust. The cognitive and/or creative work going into the perpetual earning of this trust can be thought of as taxation, in the sense of 'to tax ones wits.' Strive to continually tax yourself in this regard as you write, revise, and refine a piece of writing.
To close this essay, I wish to return to the opening thought. In a world where two sentences strung together often strikes potential readers as being 'too long' to even bother starting to read, a person interested in producing quality pieces of engaging writing must make rapid progress from a very lowly initial position indeed if they hope for their output to prove a worthy expenditure of a total stranger's time.
Consider: being forced to read something you absolutely hated for forty-five hours would be a most perverse torture - yet the same amount of time, when spent with a favorite book, could never be enough in a lifetime of years.
Strive always to turn the common reader's complaint into 'ts:dwite' - "Too short; Didn't Want It To End."