I've been thinking about the tag name and I think we don't actually need any tag at all. We should just convert to community wiki, and that's it. We still need a guideline to determine when it should be a community wiki of course. But why have a tag for it?
This. That's the answer. And the system will handle it for you...
But... Allow me to elaborate... And quote from The FAQ:
Chatty, open-ended questions diminish the usefulness of our site [...] avoid asking subjective questions where …
- every answer is equally valid: “What’s your favorite __?”
- your answer is provided along with the question, and you expect more answers: “I use _ for _, what do you use?”
- there is no actual problem to be solved: “I’m curious if other people feel like I do.”
- we are being asked an open-ended, hypothetical question: “What if __ happened?”
Right away, you should be very, very skeptical toward questions that specifically ask for a big honkin' list instead of... well, answers. List-building is popular, appealing as it does to both bored readers and OCD-sufferers... But rarely is it actually useful. Google will happily give you a big list - no telling which part of that list will actually be useful to you.
So yeah. Your knee-jerk reaction to such a question should be to close it. Close it as a duplicate of an existing, more-focused question, or close it as Not a Real Question. Just shut it down before it runs away on you...
...But on those rare occasions where the "list" is actually something useful as a list, then... Don't do anything. Really, you don't need to. Definitely don't go branding it with meta tags.
If it actually gets a significant number of answers, the system will make it - and all answers - Community Wiki. On most sites, that threshold is 30 answers; on sites that tend to get a lot of list questions, this can be reduced.
But you don't want to be one of those sites, right? You want answers to questions, help for desperate parents searching for answers in the wasteland, water of life for parched souls in search of knowledge, not rambling lists... right?! And so you'll take an axe to thoughtless list questions as they crop up, and then gently guide their authors into asking actual questions...
But... If lists are to be a fundamental part of Parenting, then you'll go post a feature-request for the 15-answer CW threshold.