I, along with many on this sub, am a lurker who loves his history, but I am also not in any means a historian. Often, however, I see questions that are a couple days old which I know the short answer to but have neither a previous answer nor sources I can really refer to, so I don’t answer. Would it ever be acceptable to PM a short answer? I know this could be very abused by users with biases to spread misinformation, and that sometimes questions can take a while to be answered, but it’s also a little depressing to not be able to help a little. Thoughts on this?
There isn't a definitive answer to that. Some OPs may appreciate it, others not so much. it also depends what you have to say.
I've been sent PMs in this situation, and occasionally they are actually useful. Might be someone apologizing they don't have the time but recommending a really good book I should check out. Or once it was someone who knew they would break the personal anecdote rule but nevertheless had a very interesting story from their childhood in Communist East Germany.
But more often... It is somewhere between annoying and insulting, depending how... useless... the message is. I have gotten PM'd "answers" I know are flat out wrong, "answers" that are just a summary of Wikipedia or the top hit from Google, or simply just the links to the same. Do they think I'm so stupid as to not know those resources exist?
So in short, it takes some objective evaluation of what you actually have to offer.
Well the point of this sub is that posters are ostensibly looking for a detailed and sourced answer from a knowledgeable party. Now as we all know many, many, many, users don’t read the rules and don’t seem to get the distinction between this and other history subs, so they may be fine with having less detailed answers PM’ed to them. But posters that asked their question here for a reason will be looking for an in-depth answer and might think “If I wanted short answers from users who may or may not be qualified, I would’ve posted to r/history.”
If I personally asked a question and someone PMed me something useful I would appreciate it. A lot of questions on here do not get answered and I feel that either a partial answer or book recommendation would be appreciated for those that are left unanswered.
Also I don't think there is any rule anywhere that prevents PM's since it isn't something anyone can easily moderate.