How to motivate users to write tag wikis?

Question

A very large number of tags on Stack Overflow don't have tag wikis at all. How can users be motivated with enough rep to write and edit them more often?

Rationale:

A great deal of users asking questions like: "Where can I find some references for X or Y?" or "How to do this most basic thing in Z?" could be simply shown the appropriate tag wiki. (Yeah, I know. It would've been better if they looked there in the first place, but many new users don't know that they exist).

I described my idea in a separate answer.

But, some of you will probably think of an even better or easier way to promote this behavior. So, let's hear it.

EDIT: OK, thanks to everyone for their participation in this discussion. We have some really great answers here, and it was next to impossible to choose the right one, partly because they are all good, and partly because of the tendency of a discussion not to have just one answer. So, I picked the two answers which seem to be supported by the largest number of users to accept and grant bounty, respectively. I hope some of these ideas will be used soon.

Answer 1

I was going to post this as its own feature-request, but since you asked the question, I propose killing two birds with one stone here:

Show the first line of the tag wiki in the auto-complete tooltip for tag entry.

That increases the visibility to normal users, which is especially important for users who are bad at tagging (i.e. almost all of them). The increased visibility would almost assuredly motivate those who are interested in having good tags (such as myself) to maintain the tag wikis, and keep them concise.

Answer 2

This answer is taken from this feature request I posted earlier.

I think requiring 100 upvotes in one particular tag to contribute to these pages is too high.

Firstly, trust the populace and put faith in self-moderation. You don't have to provide credentials to edit some detail about the decline of the Byzantine empire on Wikipedia. As always, Wiki-content quality is assured not by the reputation of the content provider but by amount of page views. If the page is called a wiki it should behave like one. Anyone, even users who are new to the site, should feel welcome and trusted to read these pages and give of their knowledge.

Secondly, the success of Wikipedia and wikis in general, derives from the fact that expert knowledge about a given topic provides only a small percent of the work necessary to make an informative page about a topic. The success of the tag wiki system is dependent on a veritable army of people who relentlessly fix grammar, review the text for clarity, re-organize content and provide new links. In fact, the people who are qualified and probably the most motivated to make these necessary changes, to give these pages traction, are the non-experts who come to those pages to learn from them!

(A similar request - now status complete.)

Answer 3

A small idea: On the user page, put a list (or link to one) of unwritten tag wikis that the user qualifies for as a potential writer.

Answer 4

tag-wiki excerpts now appear on the on-hover tag-bubbles. This is a great reason to at least create those tag-wiki-excerpts!

Answer 5

My own idea was a badge awarded for N created/edited tag wikis. It could be called Encyclopædian (name taken from: Additional Badge Ideas). It definitely promotes the good behavior, and if it works well might result in a whole network of the material useful to, say, anyone who is just starting to learn a new programming language, framework, etc.

Answer 6

Just had another idea as I was posting a question. On the "Ask a Question" page, along with the "Related Questions" section, why not pull up the tag wiki pages for the selected tags and/or tags matching the question title? That would give them a lot more exposure, and at a point where they're most likely to be relevant to the user.

And as users see that the wiki pages are getting increased attention, it should provide more incentive to create useful wiki pages.

Answer 7

Perhaps the bar for editing privileges should correspond to the amount of activity in a tag? New tags have little activity, and are most in need of editors, so let anyone with a few hundred rep populate them. As activity in a tag increases, they need revising rather than wholesale rewrites, so the bar can be somewhat higher. Established tags like Java and C# only need the occasional update, and are more tempting targets for spam, so they can have the highest editing rep requirements.

Also, eliminate the top 20 answerers/100 score requirement for young tags so people can get the tag wiki started.