I will point out that though the wiki hammer doesn't count as an edit, it does show up in the revision history. If a post has not been edited, then there is no direct link to the revision history, but you can get to it by going to the URL http://mathoverflow/revisions/XXXX/list, where XXXX is the number of the post. In this case, you can see that Scott converted the question to wiki.

But I still hold that this question was different. Anyway, it seems to be going pointlessly ad-infinitum; it is not that the world hinges on this question.

Edit: Regarding the subject at hand, as I think I explained in the comments, the rule of thumb is that a non-CW MO question should have the property that it is possible to agree upon what constitutes a reasonably complete answer to the question, and therefore to accept it, giving the answerer his credit. Big-list questions have the property that it is not reasonable to accept any one answer, so along with other questions that have this property they've generally been community wiki.

This makes sense when the list is a list of references, for example, which do not take a lot of effort to write down. However, I see your point that in this case the answers are not trivial to write down and deserve some credit. We don't at the moment have a way to prevent the questioner from gaining reputation while the answerers do.

Edit #2: Let me mention some other reason big lists are generally community wiki. First, it lowers the entry requirement for users to edit each other's answers, so if an entry on the list is interesting but poorly written it is easier for someone to write more about it / give more background. Second, it allows the voting system to be used more effectively to rank the list without damaging the reputation of users who give bad responses.

On the other hand, in general it might be a good idea to require that both questions and answers should be community wiki, for questions like the two examples in the above line.

There is a difference between this big list, and a big list asking for books on algebra for instance. I hope you understand my point.

Edit: As I think on it, I think I had commented first, and then it was later made wiki. But again I do not know with complete surety. But this is not the important thing.

The important point is that the answers were good, and nontrivial to come up with, and each responder deserved the rep s/he got. This was a case different from the usual wiki cases attempting to gain reputation with soft questions and soft answers, I believe.

If I made it community-wiki after you'd expressed reservations about it, I'm really sorry --- I didn't expand the comments before going ahead. I made it community-wiki on the rule of thumb that all big lists should be. I'm happy to hear what people think on this point, for the future, however.

In fact, I have yet to understand when turning a question into CW is good («I want to know this, but I will set things up so that you, if you answer, are not rewarded neither by me nor by anyone else»)---I can see, though, situations where it makes sense for an answer to be made CW.

I was thinking that it was rather some automatic software action, like big list --> community wiki.