Can we use Fanfiction.com as a metric for what is the most popular franchise ever?

[Saint of M]

At times, though it can come back. Warcraft for instance, tends to get a surge every time an expansion is released, but then settles back down.

Yeah, actually. I remember seeing a chart showing the spikes that correspond with every piece of released new, original content. WoW expansion packs are treated kind of like new game releases, as subscriptions (and total profitability) spike and then fall off the face of the Earth with every grace period of new content. Plus fanfiction.com isn't probably a good metric as multiple fandoms tend to produce other sites, and it depends on the quality of those other sites UI and author base that may determine its propagation of fanfic.

I can also see waring fandomes upping the numbers just so their favorite show or ship is going strong, despite the popularity or even qualety of the source materail

 

[Hawki]

I can also see waring fandomes upping the numbers just so their favorite show or ship is going strong, despite the popularity or even qualety of the source materail

Having posted on ff.net since 2006, I've never encountered any "warring fandoms."

That said, there are many cases where I've basically single-handedly created a category and filled it exclusively with my own fics, but the quality of fanfiction in of itself says nothing about the quality of the source material. For instance, I think Section 8 is a terrible game. Didn't stop me from writing for it, including a multi-chapter.

 

[KingsGambit_v1legacy]

Kinda but not always. While there are some obvious bits of info to be taken from it, some authors are quite strict about not having fanfiction written in their world or about their characters.

One of JK Rowling's greatest triumphs, in addition to inspiring man young readers, was also inspiring many young writers. She went so far as to not only allow it, but encourage it, something I think she deserves major kudos for.

A useful point of reference, tho likely not exhaustive by any measure: Fanlore.com

The main issues revolve around commercialising it, making it adult where the source was more PG, damaging the original work and some other points.

Harry Potter is going to be by far the biggest for books, I cannot speak on the others.
Interestingly on the subject of Batman, he'll be public domain in 2034 (and Superman a year earlier.) So it will actually be possible to commercialise an all-new story about Batman, at least as he existed in his original incarnation, by anyone. Technically. We'll find out how that works in...15 years

 

[Hawki]

Harry Potter is going to be by far the biggest for books, I cannot speak on the others.

Top ten are:

Harry Potter: 797K (used to be over a million at one point)
Twilight: 220K
Percy Jackson: 75.4K
Lord of the Rings: 56.8K
Hunger Games: 45.7K
Warriors: 25.9K
Mortal Instruments: 17.6K
Maximum Ride: 17.4K
Hobbit: 12.5K
Chronicles of Narnia: 12.3K

I've posted in five of those settings, I'll let you guess which ones.

Also worth noting that the list can kind of be misleading. For instance, Percy Jackson gets an entry, but every "Riordanverse" series gets its own entry (Carter Kane, Magnus Chase, etc.) Plus, the Hobbit section was pretty dead before the films, at which point they skyrocketed.