I am with you on that feeling about AO3. I think it definitely feels like a more public space than a journal. You don‘t necessarily get to know the creators either, as many haven‘t even filled in their profile. Many don’t reply to comments at all (and they aren’t obligated to - this is the main fannish convention that makes things feel so different over there IMO).

The exception are people who make extensive use of the 'notes‘ feature. I always feel like those are more approachable and you can get to know them a little over time. And sometimes I have had conversations in the comments just like on a journal. That is very rare though.

I do like that the kudos feature makes it easier for lurkers and shy people to let me know they enjoyed something.