Part of it is the sheer volume of traffic on FFN. Most of my recent stories have ended up getting around 1000-1200 hits, with an average of 5 meaty comments per chapter (and that's a relatively low number of comments per chapter - some of the more popular writers in that fandom will get 10-20 comments, not sure how many readers they have, then again some of the writers I like best will not get as many as I do). So that's what? Roughly 200 hits per meaty comment. Yet on AO3 the most hits I have gotten for a story with one chapter is 116, and most of them have had fewer than 70 hits. That could have more to do with the fandom itself and where the bulk of them prefer to congregate. Actually, doing the math, the long multi-chapter story did get a comment to hit ratio of 1:200ish on AO3 - but I have not figured out how to parse the traffic counts against the chapters (FFN does give a breakdown, so I can have something remotely resembling a reasonable estimate of how many readers had to go back and read a chapter or two to refresh their memories in order to make sense of a new one I posted).

To be fair, it's worth looking at the relative ages of the two archives, and the user-base. AO3 opened for business only three years ago and still draws primarily from the slash-oriented LJ/DW-based fannish community (take a look at the Recent Stories page--there's a ton of Sherlock going up, which I suspect is barely on the radar at FFN). FFN has been around for what, fifteen years now? And has millions of stories, in tens of thousands of fandoms.

There are fandoms that grew up almost entirely on FFN, and have minimal traction elsewhere, so that naturally those stories will get more hits on FFN than anywhere else. And vice versa.

Additionally, the response on AO3 is very time-sensitive. By which I mean: Yuletide stories on AO3 get LOTS of comments. Stories posted to AO3 as part of an active fannish community which is using AO3 as its primary archive--like Vorkosigan--get lots of hits and comments.

But when I put my old SPN fic up on AO3, it doesn't get a lot of hits, because SPN's start as a fandom predates the development of the archive. People who are reading older fandoms on AO3 don't comment on older stories as much, because, well. For the same reason nobody comments much on older stories in any fandom--the reader perceives the conversation to be over.

It also depends on social conditions. I posted Carpetbaggers on FFN and AO3: I got about ten comments on FFN and sixty on AO3. Mostly because I was an unknown in Narnia fandom on FFN, whereas people on LJ/DW knew me and were willing to give me a chance, even if they didn't consider themselves part of Narnia fandom.

AO3 is, admittedly, less social than LJ/DW, but I think that varies between fandoms, and is also not necessarily a bad thing. Lots of people who wouldn't comment on a story at least have the option of the kudos button.

I dunno: I like AO3 for story-management purposes, and the concept of a long-lived archive I don't have to maintain myself, but I don't think there is such a thing as a perfect archive where everyone gets all the feedback/social connection they want.

I don't have anything up on FFN. What little fic I've written was either sent out to email lists or put up via LJ. I've moved it to AO3 for archiving purposes and get the occasional kudo. Which is nice and more than I was expecting. But I have't written anything in years, so I don't know how AO3 would be for a more active fandom (i.e., not Sith Academy, Farscape, or West Wing).

I like AO3 because I never had a hit counter before, and it's interesting to see how many times a story is read. I'd love to know if older stories of mine on LJ got as many hits.

I also think offering the "kudos" option was both good and bad -- good because it gives people a chance to at least indicate they like a story even if they don't want to bother to comment, and bad because it's then much too easy just to click and not comment at all.

But I have't written anything in years, so I don't know how AO3 would be for a more active fandom

I'm not writing in it, but I read a lot in Vorkosigan, and there are some active challenges hosted there--it does pretty well, so far as I can tell. The key is that new stories are posted there, and announcements direct people there, rather than just use it for a backup.

They have a subscription service, which I like, but I would like to expand that so I could subscribe to a particular fandom, rather than a writer. Or even a particular tag.

When you subscribe to something on AO3, does the author know?

Not so far as I can tell. Certainly I have no messages regarding subscriptions, although that could mean nobody has subscribed to me.

(take a look at the Recent Stories page--there's a ton of Sherlock going up, which I suspect is barely on the radar at FFN).

Nah. When I run out of AO3, I hit ff.net for it. There's plenty.

Though many of the ff.netters are starting to crosspost to AO3, which, err, kind of makes me sad, because there's been a serious drop in quality with the increase in quantity.

I love the kudos button. I got a kudo this morning on my Yuletide, and it made me smile. It also makes it easy to thumbs up from my phone.

When I was writing a lot, I grew to fear comments. There's only so many times a body can write, "thanks!" before it starts to feel forced.

I never got enough comments for that to be an issue. It helps when people leave some substance in their comments, but still, really not a threat for me to be running out of words.

Yeah, "thanks" seems to be more than enough of a response to "grate story!"