The idea of self-answers seem to be slightly against the primary purpose of this site. This site doesn't want to accumulate the kind of junk other sites tend to (I think). Also, this site wants to become an encyclopedia of non-trivial, useful information in the form of questions and answers.
But if self-answers are allowed, then the question-answers (might be) more inclined towards being trivial or not useful for a lot of people.
My question is: What kind of self-answered questions must be promoted to be more suitable for this site. What kind of topics? etc.