There was a line one used to hear about Sherlock Holmes that there was more written about him than any person except Jesus, and perhaps Napoleon. At this late date, I'm not even sure where that entered my brain from -- a John Bennett Shaw workshop, some pre-WWII bit of Sherlockian scholarship, or where. As the Napoleon reference would imply, it goes back a long way. You don't hear much about Napoleon fandom outside of "The Adventure of the Six Napoleons" these days.
But that line never saw fan fiction coming, nor the effect the internet would have on it. That combo was the invention of the nuclear warhead in some respects. We went from a day when fan fiction still had publishers, as amateur as they were, and editorial gatekeepers of a sort, even though self-publishing was always available if you had the time and bank account. Now bank account and access to a local printer (the person/business, not the household appliance) are no longer necessary.
At this point, if you can write it, putting it out for the public to see isn't a problem. You don't have to painstakingly type it out on a typewriter, send it to a typesetter (unless you were typesetting with a typewriter), get the type laid out and to a printer, with all the details in between. Now you can just type it up and push it to the web, just like I'm doing here. These words could be a scholarly essay, a short story, a novelette, or a full chapter-by-chapter novel if I so desired. It's just that easy now.
Which changes the dynamic a lot. Suddenly writing about Sherlock Holmes is as easy as reading about Sherlock Holmes. Writing well about Sherlock may seem harder than reading well about Sherlock, simply because reading is not usually done in public, so we never know whose out there struggling with literacy just to get a dose of Sherlock. With writing, we can pretty much see who did well in English class and who didn't . . . or who made the effort to improve their skills later . . . but if you really don't care what anyone says about your stuff, you can publish it anyway. (Hmm, just realized that "publish" and "public" probably come from the same root. Interesting.)
All this means that we have more writers about Sherlock Holmes than we ever did.
Last year at 221B Con, I had a great time at a midnight fan fiction workshop with what seemed like a couple of hundred other people doing fan fiction writing exercises. Think about that -- well over a hundred people in one spot caring enough about writing Sherlock to stay up past midnight to do it. That isn't writing to become famous or writing to make money. That's just writing for fun, like going to a karoake bar or going dancing.
Writing doesn't have to be about fame or fortune. It never did, it's just that those ideas are like the big Powerball lottery jackpots, hard not to let your daydreams drift to. If you've got the talent, the drive, and/or the connections to get your work out ahead of the pack, you can still go pro with wordsmithing, but you definitely don't have to. We now live in an era where an adult can read comic books without posing as a "comic collector" to try to legitimize the hobby, and writing is much the same. You can write whatever silly-ass thing you want just for your own enjoyment, just like you'd paint an acrylic nature scene without ever considering a gallery show.
That's why I enjoy blogging in the mornings. Gets the brain going, orders the thoughts a bit, and can be a sort of relaxing meditation. At this point, I think I'd be doing it whether or not anyone read it. But it dumps just that many more words into the mass of public writings about Sherlock Holmes.
We have to keep ahead of the Trekkies, Potterphiles, and those pesky Napoleonianiacs, after all.