As a matter of etiquette, what is the MO policy about "closed" questions? Browsing MO recently I came across two cases

http://mathoverflow.net/questions/28400/an-inequality-question
http://mathoverflow.net/questions/31140/equation-system-question-closed

where the original posters (I assume they are different individuals) "closed" their own questions by replacing the question text with the phrase "question closed". As a personal opinion I feel rather annoyed at this, especially in the first case (where Scott was nice enough to revert the edit and put back the original question text) where the question may be a genuinely interesting one, and the answers and discussions are of some merit. I have been under the (perhaps incorrect, as there's nothing to this effect in the FAQ) impression that part of the reason for MO is as a publicly available and searchable record of what has been discussed. Somewhat reinforcing this notion is the idea that duplicate questions are discouraged. To close a question by essentially deleting the question text is contrary to what I thought of as the spirit of MO (again, I may be under a wrong impression).

What are people's thoughts on this?

In this case, it looks like OP added their second question to http://mathoverflow.net/questions/30983/ . So there's no real loss.