Assuming:
- The majority of stories (60%) is at or around the Fimfiction minimum of 1000 words;
- Around 30% of stories are around 10K words, or a smaller story.
- Around 9% are longer stories of 100K or smaller.
- One percent are stories like Background Pony, or the End of Ponies, and stretch past the 300K mark.
- There are a few outliers that stretch to 600K+ words. We'll just call them a round 2.5 million for the whole of them. This includes Project Horizons, a Dangerous Business, Fallout: Equestria, and other doorstoppers.
If you total all the stories and run the numbers, you wind up with a total of around 3.68 billion words, all in the space of two years. That adds up to 504 thousand words per
day.