Crit bookmark anon had it mixed up on one point, the rule of thumb is that expecting authors to specify what form of feedback they prefer is rude, burdensome, ableist and so that hurts their feelings too, or that's how it's been explained to me.
Personally, I swear when I got into fanfiction around 1998 concrit was the holy grail of feedback that authors asked for with the desperation of a starving populace, but the vehemence to which people say it’s always been this way, that c+c is c+c+cruel, that authors have never needed to state their preferences, to the point of insulting me is actually beginning to trigger my psychosis and make me doubt my own memories.
It makes me nervous to even read fic anymore because I love expressing my love. People tell me they love my reviews because they're "juicy and detailed" since I do my best to put effort into picking out the parts I really loved around and the parts that confused me (if there were any). They’ll thank me for my feedback, and then they’ll say concrit is cruel actually and discourages authors, is ablist because of the possibility for rejection dysphoria, that what I did wasn’t even actually c+c but all I did was analyze their work and review using the crit sandwich. By the very definition it seems to me to be critique but I have no idea anymore!
Hell, it even makes me feel insecure as an author. Glaring mistakes get complimented, it’s like someone saying my smile is beautiful while I have a huge hunk of food in my teeth. Like I’m glad you said you liked it but are you lying to me? What are your genuine feelings? If you’re an author, why don’t you want to just post your house rules? Is it because I’m just being intrusive? They say I should ask what the house rules are to be considerate about their feelings, but treat me like as a reader I have none to be considered.
It’s got me wrung up, clearly.
I've tried to encourage people to feel safe with c+c in my comment section and other authors still get mad at me for doing it that way too because it's damaging to them as a writer because I’m doing fanfiction wrong.
Has it always been like this? Am I actually delusional? Please tell me I’m not just going crazy and you’ve been noticing this as a cultural shift too, if I’m alone in this I think I genuinely might be sicker than I thought I was.
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I don't think it's a clear cultural shift in one direction, but yes, I've noticed things.
I think AO3 culture owes a lot to LJ culture and LJ culture was often less into crit because the fic was so visibly in the author's personal space. A lot of LJ authors also had circles of beta readers and good friends who were quite visible, so concrit from others was superfluous and not so helpful. At the same time, LJ being a blogging platform meant that people could rec in their own journals and include concrit in that context easily. AO3 doesn't have much of a space for meaty reviews, though you can try with bookmarks.
Meanwhile, mailing list culture was often pro-concrit, and so is FFN. Forums are often pro-concrit. Some of these are older spaces, but they're also just different spaces from AO3.
A lot of "changes" are simply a change from being used to some other space to AO3 getting so popular everyone's crowding in there. The old culture persists somewhere else.
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My own view on concrit of my work is that it doesn't hurt my feelings, but I don't find it useful, so I don't think people should waste their time on it. Good concrit is hard and it takes a while to write up.
Once I post a work, it's as done as it's going to get. Many people who've critiqued me in the past have also just had bad quality advice. I've sat in (non fandom) writing groups filtering the often also very bad advice there, and it's not just ego: I have a pretty good handle on which critiquers know their stuff, and most do not. I have a couple of friends whom I let read my pro writing because they know what I'm going for, and I understand and trust their taste.
Now, if someone wants to critique my finished fic in a review, that's fine by me because even though the work is done and not getting edited again, the pros and cons are worth noting for a future reader.