Following on from Check mark discoverability seems to be low for new users, I've taken to commenting with the following proforma whenever I see
a 0% accept rate a question from a new user who has asked multiple questions, but never accepted an answer (especially if they have indicated in comments to previous questions that an answer solved their problem):
Welcome to Stack Overflow! I can see that you asked a few questions here before, but haven't marked any of the answers you received as accepted. Accepting answers rewards the poster and shows the community that your problem has been solved; you can also upvote any post if it's useful or helpful. Please take a moment to revisit your questions and accept answers that solved your problems: it will make people more willing to help you in the future.
In response, I was recently pointed by another user to the meta discussion Is it appropriate to comment on people's accept rate? (of which I was already aware and indeed had devised the above message after reading, intending to be as helpful and friendly as possible). For the record, since reading that discussion, accept rate has not stopped me from answering questions.
Clearly, some think that the above message is still poor etiquette: but it was intended to help inform new users who may not understand the workings of the site. I would have liked to include further information about posting & accepting one's own answers to questions solved by oneself, or promoting/improving questions that have not yet been answered satisfactorily, or deleting questions that cannot be answered—but sadly there was not room to do so without losing other useful information.
I was going to request a feature to notify users with 0% accept rate that they should accept answers, but clearly that would duplicate Show alert for users with 0% (or low) acceptance rate. Whilst a feature like that would negate any need for the community to provide new users with such guidance, in the meantime many new users remain unaware about question acceptance.
I would like to know whether attempts to educate new users in the way I tried are indeed poor etiquette?
To those who argue that users should be free to leave resolved questions unaccepted should they so wish, my view is that such non-acceptance is harmful to the community because:
future visitors can't be certain whether their identical problem ought to be solved by any of the answers (and certainly the answer that solved the OP's problem may be buried amongst other answers, rather than highlighted and shown at the top); and
helpful users might keep coming back to the open question (e.g. through the "unanswered" tab) thinking that further contribution is being sought, only to frustratingly find that the question is answered: this discourages use of the "unanswered" tab and makes genuinely unanswered questions harder to find through the noise.