The tag wiki is a great idea, but it is lacking some features to make it more useful.
For example, Gordon posted an interesting "reference" question with non-searchable PHP symbols (so people don't repeat the same questions over and over again). IMHO that is NaRQ but still a valuable resource. That was great material for the php tag-wiki, but it is very messy as it is.
I think common questions for a particular subject, eg: "references" should be in their tag-wikis. But for that to work well, there has to be a way to better organize the tag wikis. So, I think we need:
- Better formatting for tag wikis
- Better ways to structure content:
- An outline feature
- Sub pages (perhaps?)
Also I think wiki material should be included in searches, and featured prominently (like Google does). eg: if I search for "sql many-to-many" and a tag-wiki reference exists, it should be seen maybe on top of the questions.