Over at physics.SE, I've noticed many questions in the "unanswered" tab, which have excellent answers but aren't accepted. It could be for two reasons:
- The OP didn't get an answer in xyz days so they forgot about it
- The OP didn't realize that questions can be accepted.
I mainly want to address the first. Here's my proposal: When asking a question, a new user (one who has had nearly no activity) can get a little popup--the yellow type-- which asks him if he wants an email notification on receiving an answer on that question. I know that there are issues about spam; so I think that it should be limited to that question only, and the page should have a prominent "you have email notifications ON for this question. Do you wish to turn it OFF?"
For the second, I feel that a yellow popup "use this button to accept the answer" over the accept button (automatically opens on page load) should be enough; though I don't think that this is the primary issue.