There are two situations that I've seen that are very specific to the vi stack that may not exist other places. Both of these probably should be discussed.
An Example Plugin
There are many times when someone will ask how to perform an action, either in the form of manually typing it out, or to put into their vimrc as a simple script. A lot of times people will post comments stating that the "problem" has already been solved with a specific plugin and you should just install it.
In cases where the question has a very simple manual solution and someone posts a much more complex plugin, I think this is probably a good situation to post in the comments. If someone points to "The Kitchen Sink" plugin that does everything, its not really answering the question. However if someone posts a plugin that directly addresses the question then maybe it should be an answer. If OP ends up using that solution...isn't it the answer?
Personally I'd prefer to post the one-liners and simple functions here and then link to the project so that people can learn how to use vim, write vimscript, etc.
What you asked isn't correct, but I know what you are getting at
There are many times when someone is very new to vi/vim won't fully understand how modal editing works. They will ask a question using wrong terminology, and be mistaken in how things work in different modes. More advanced users will many times understand what OP was trying to get at even with their lack of knowledge. Hopefully someone comes in and edits the question to fix those problems, but before that happens I've seen a lot of answers in comments that start out with "What you asked isn't correct, but I know what you are getting at..." They then go on to answer the question in a comment.
I can understand that some people might feel that since they aren't answer the actual question (since the actual question is flawed) that they should post in the comments. I think this is the most annoying situation we encounter that is very specific to this stack. If you think you know what they are asking, then answer it. If you answered it incorrectly, OP has no obligation to select your answer. Use the comments to figure out what they truly are having issues with, and then go edit the question to it works.
When you go to write a question SE tells you to search for it first. If you don't know exactly what you are trying to do, you will probably have difficulties looking it up. If you do a search and all the questions come up with 0 answers, is anyone really going to open the question and dig through the comments?
I've noticed that on SE that a lot of people are afraid of giving the wrong answer. Its one thing when the topic is more theoretical but when it comes to this stack, most of the questions are "How do I turn X into Y using vim?" If your method works, but only in specific cases, post it. Someone might learn something from your example. Heck, we have vim golf, so we all know there are many ways to solve a problem with vim.
I also have noticed that on SE people tend to take small steps to a solution using comments. I don't like this approach because you end up getting a lot of "Try X, did this fix it? No, then try Y." The answers can be edited so why not give an answer and let OP submit a comment. If you came to a partial solution but in the end wasn't exactly what OP wanted, make another answer and leave the old one around for future visitors to learn.
Lastly, I was going through the unanswered questions from the past few months. Saw there were tons that had 0 answers but when I went to go answer I find that the answers are in the comments. We don't have any where near the backlog of semi-answered, but no answer selected questions as many other stacks have. But I find it odd, that with how everyone uses vim differently, we aren't seeing every question have 5 or 10 answers. I just answered one where I could have gone the function route, could have done a one-liner, could have modified default functionality or I could have used the default rc and just been more aware of all the key bindings. In the end, there were 2 solutions given, when really there could have been 4 or 5.
