“You also raise an interesting point about specialized wikis. Don’t they represent a threat to the mass-market Wikipedia? In other words, as power Wikipedians divert their attention to the specialized wikis, this reduces the attention paid to the main site.”

As Wikipedia takes a deletionist turn, moving content and contributors to specialized wikis certainly does seem like an attractive move. If Wikipedia (WP) doesn’t appreciate you, take your efforts to a wiki which will! And if you start your own, you can be Administrator, Bureaucrat, Steward, and policy writer all rolled up in one. But this is a rosy dream for most.

The fundamental fact is: Specialized wikis can compete effectively with WP, but only if the WP let them. It is WP’s game to lose. The other wiki can win if certain conditions controlled by WP are cleared.

The advantages The advantages of doing all your work on WP shouldn’t be underestimated: access to a large pool of competent editors, with low transition costs - for example, it would be free for me to switch from working on, say, medieval history articles to working on Star Wars articles, because the methods, organization, templates, customs and so on are mostly identical; because my account and reputation follow me there; because all my customizations and personal tools like custom JavaScript or text editors will be equally applicable in the new area, and so on. This is not true if the medieval articles and Star Wars article are on entirely separate wikis. A skilled WP editor switched to another wiki will flail around: why is MediaWiki acting this way, where did that option go, who on earth approved these pictures, and how do I get the table of contents back? There are also network effects to consider - pretty much every article sooner or later needs to link out of its specialized area to more generalist articles. If the separate wikis have interwiki linking set up, it isn’t all that much harder to link to articles on other wikis than it is to link to an article on the home wiki, but that’s an esoteric and not popularly well known feature, and even at its best still adds friction to the work. And there are many other subtler advantages hard to enumerate and appreciate until one works on a small & non-Wikipedia wiki.

Necessary conditions So the only way a specialist wiki can survive or thrive is if it is on a topic Wikipedia refuses to cover. Examples I was involved in the Star Wars area of the English WP for a long time, and it did well, until it began to do too well: editors from other areas saw the detail and profusion of articles in the SW area, and began moving to trim them down drastically and raise standards for the surviving articles. In other words, WP in a very real & important sense just decided to stop carrying SW articles. This rejection prompted most of the hardcore SW editors to fork and begin building Wookieepedia (a SW wiki hosted on Wikia) using the base of SW articles from WP. Now their resource is so good that SW editing is mostly dead on WP, with the exception of a few editors like Deckiller who focus on organizing and removing and improving what’s left, and occasionally borrowing articles from Wookieepedia on the notable new or missing stuff. A similar example happened on the Polish Wikipedia with railroad articles . Similarly, Wikibooks works because the Wikipedias refuse to carry detailed ‘how to’ manuals and expository works, but people want to work on textbooks anyway. (They aren’t so good at finishing them, though.) In contrast, Wikimedia Commons doesn’t have the mind-bogglingly vast collection of media and users that it ought to have, because editors can still upload everything to their Wikipedia - they haven’t been forced out to Commons . Potential wikis Frequently in communities, I see proposals which go ‘let’s create our own Wikipedia about our favorite subject, X!’ The proposers see clearly that there’s a body of knowledge which can be written down concisely and polished as a standard community-wide reference (like the old FAQs that Usenet groups would maintain); but what they don’t see is that they are trying to compete directly with WP and are doomed. As the Zawinski quote about regexps goes, now the proposers have two problems. I saw this recently on Imminst.org, one of the largest communities devoted to discussion of supplements and substances which enhance mental performance - since WP only covers nootropics to the extent that information appears in peer-reviewed studies, they should start their own wiki and write better articles. Such a proposal is pretty much doomed, although since nootropics hobbyists (like myself; see my own experiments) are heavily academic and techie-oriented, such doom may be very slow and drawn out and waste a lot of effort before finally expiring. So what should Imminst forum-goers do? As above, they should cover what WP won’t. In this case, any Imminst wiki would at the beginning of each article point to WP’s article for all the important background, and then immediately proceed to non-RS or peer reviewed material: what does the mass of anecdotes say this nootropic does, what nasty effects have people reported, where can one buy it and for how much, what does it synergize with (‘stack with’), what novel conclusions have we drawn from the research literature and general biological novel (stringently banned on WP as ‘original research’), and so on. The instant anyone adds RS or peer review material, if possible, it should be removed and inserted into the main WP article. If an Imminst wiki tried to write its own Wikipedia style, it dooms itself to writing stale half-assed articles which no one will read. (WP is so popular that even highly niche areas can kept up to date by random anonymous editors without any regular editors specializing in the subject area.) As time passes, a cleavage will develop - if you want background information, you go to Wikipedia; if you want in-depth and practical information, you go to the Imminst wiki. This is a sustainable and useful situation.