How the Heck Did That Happen? · 3:54am May 4th, 2015
I have to say, I am pretty amazed at the reception The Rainbow Pony has gotten. With the current like:dislike ratio at about 14:1, I'm pretty thrilled. I wasn't expecting everyone to like it, so the downvotes don't surprise me at all.
As most of you have probably noticed, most of my stories up to this point have been primarily SoL or Comedy stories. The Dark tag was very new territory for me. The fact that Rainbow Pony got into the Popular Box (and was there for almost two straight days) was really unexpected.
I clearly have you guys to thank for that, so thanks a lot! 
The bit-by-bit publicity is gradually earning me new followers. I must admit, I love seeing a number above that little bell up there, whether it's for new followers, or feedback on my stories. It means I'm doing something right, or getting comments that will move me in the right direction.
That being said, there are a couple of people that were a little lost with a couple of aspects of the story. I hopefully gave suitable explanations in the story comments, but if there are any other questions about the story (or its background, which would open up a whole other kettle of fish) that anyone wants to ask, I'm opening up the comment section in this blog post for discussion.
So, if anyone is reading this blog post and hasn't read The Rainbow Pony yet...
SPOILERS BELOW
Now, since there's a likelihood that I may reference it in some of my answers, here's the encyclopedia entry that Scootaloo read. You may find some answers there.
The Legend of the Rainbow Pony
While its specific origin is unknown, the legend of the Rainbow Pony is said to originate from an early Pegasus tribe, before Equestria’s foundation. Originally thought to be an old ponies’ tale, the story of the Rainbow Pony turned into legend when pegasi began telling of events similar to the tale happening in real life. The legend says that ponies ‘whose hearts are true’ may make a wish for the Rainbow Pony to fulfill. However, before their wish can be granted, they must complete a unique task assigned to them by the Rainbow Pony. Ponies learn of this task when they receive an item wrapped in noctis wings— it is said that the task is never explained, but that they simply know what it is when they receive the item.
The Rainbow Pony has never been fully seen—it is assumed to be a pegasus due to the story’s origin—but the subjects of all accounts mention that a prismatic tail vanished from their view just before they received their package, thus leading to the legend’s title. All recorded ‘sightings’ of the Rainbow Pony had similar factors. The noctis wings the subjects received their items in appeared to have been genuine. While there seemed to be no sign of forced or surgical removal, nopony knows if the wings were taken from a live noctis pony. The items the subjects received were all, to their shock, a pony’s bone. The bone each subject received was somehow related to their wish (e.g., a pony who wished for financial assistance received a navicular bone, likely relating to the phrase ‘itchy hoof’). Finally, and possibly the most important, all subjects refused to reveal or attempt their ‘assigned’ task.
The tale of the Rainbow Pony lasts in today’s legends, but no new accounts have been recorded for centuries. While some believe that, should it exist, the Rainbow Pony had dark intentions, compensated for by its bright colors, Equestrian philosophers believe that the supposedly dark implications of the tasks are a message to the wisher— that they must face the trials or tribulations they are meant to face, instead of attempting to take a shortcut by making a wish. Given that the tellers of all the accounts refused to even share the task they were ‘assigned,’ it can only be assumed that the tasks are intentionally so horrifying or costly to them that they would not dare attempt them, and instead be forced to face their hardships head-on. All accounts confirm that no subject attempted their supposed task, and no harm ever came to them for it.
A strong message given through potentially controversial means, the legend of the Rainbow Pony is still commonly told amongst pegasi to this day.
Oh, and for anyone who was confused and/or didn't want to look it up, here's a screenshot from Google.
3043392 Exactly. Frankly, even I didn't understand some of what happened.
The fact that the story made any sense at all to that many people is nothing short of a miracle.
What is/was Scootaloo's task?
3045992 Ah yes, the question of the hour.
That's the point of the story— that's for you to determine. What would be so horrifying to Scootaloo that when she read that the task was actually a message and not an assignment, she would be so relieved that she didn't have to do it? Keep in mind from the entry (which yes, I added after you posted your question), the bone she received is related to her wish, not her task. I fear I may have confused some people on that.
While my intention is for readers to determine the task on their own, the one I kind of hoped would be the first anyone would think of was to murder either Rainbow Dash, or Sweetie Belle and/or Apple Bloom.
A bit extreme, I know, but that's the whole point— it should be something she would never want to do.
3046461
The first option in your spoiler wouldn't allow for fulfilling the wish.
Like a number of other readers, I would have liked to have more information, although you're not the first author to intentionally leave some things open to interpretation.
I suppose my biggest question is how many ponies, after making the decision not to attempt the task given, fulfil their own wish through hard effort? I think the story's myth would be all that much more interesting if it was 100%.
3810419
Right. That would be a lose-lose situation, specifically designed so that Scoots would never attempt the task. The second option is just cruel.
Yes, the open interpretation was kind of the whole point—leave the level of creepiness to the readers' imaginations. I appear to have succeeded on that front with many people, but obviously I didn't strike a chord with everyone. I really wasn't expecting to.
To answer your bigger question, my thought process was that people would assume it was 100%. After having such an interaction with a mythical figure, you'd think they would work harder at it on their own. However, you make a valid point—I didn't clarify that, so there very well could have been ponies that just gave up. My headcanon for this story is that there was a 100% success rate, so if that makes you feel any better, there's your answer.
3810436
Yeah of course they would work harder, but some wishes might have a 0% chance of success without certain amounts of external or supernatural help. For example, an orphan wishes to speak with their deceased parents one last time.
Although I suppose that in Equestria, the supernatural is just natural...