The things that differs from SO and a normal wiki is that the status of ownership has a completely different meaning.
In a place like Wikipedia you want to create listings of ideas and define them. Thus, each repetitive edits and changes to the original post are refinements on the original idea. However I would be very surprised to find that there is a strong correlation between the author of the idea and the original author of the article. Thus the original poster is just the first in a long string of refinements (at least one hope so) that should converge on the most correct definition.
In SO however, the original poster asked a question, thus he has a vested strong interest in what will be the answers provided. Also, edits will be mostly to correct errors, or rephrase the question so it is better understood but must remain in the spirit of the original, otherwise it is a different question. Thus the original author, however badly worded his question was, should always be present as the author of the question. Not so much as a token of ownership… but as a token of interest. Then, if you wish, you could create a metric as to the largest contributor to the question.
Thus I changing the signature at the bottom when one does an edit (whether be typos or complete rephrase) will hide the original person who asked the question. If I can make a parallel for a classroom, where a student would ask a question, of course the teacher will address the whole class in answering this question as he/she knows full well that if one student asked it, 10 others are just burning to ask it as well. However, even if another student added to the original question, a good teacher will always return to the first one who asked and ensure that the question was answered to his satisfaction. I find that not doing so is a disrespect to the student who dared ask it.
The same goes to SO, although questions benefit the whole community, one must never loose sight who asked the question in the first place, after all, of all interested people in the answer, he surely is the one who really want the answer the most.
The answers however is a different game, they are more like wikis in some regard as the goal here is to provide the best possible answer. Thus it should be encouraged to modify an answer rather than creating a new one thus creating the convergence effect of a wiki. Ownership tokens here are not as important and thus, the metric could simply be the person whose contribution was the largest according to some metric. Maybe have different metrics to measure different aspects of contributions, however the original person who answered is, in my opinion, more like the original poster of a wiki article, just the one who submitted a good draft to work on.
anyways… my 2 cent on the subject
