The game DevMaster Wiki seems inadequate compared to Wikipedia, which has far more contributing users to it than DevMaster's wiki does. However, more specific things that aren't covered on Wikipedia (perhaps for being too technical, guides, how-tos, etc) could be on DevMaster's wiki--and deleted gaming-related articles (like my recent Action (gaming)), which I've added to the wiki (as just action).
Yeah, the wiki has regrettably fallen into disuse. However, there's also the Game Programming Wiki, though it seems to be more about engines and tools than about actual programming techniques.
\...I hate when multiple wikis exist that cover the same topics. I'd rather have a single wiki that covered everything, like Wikipedia, but even that is too anal and limited (can't have dictionary entries, everything has to be referenced up the ass, contradicting/conflicting policies/guidelines, etc). It's a pain in the ass doing interwiki links (as can be seen on http://www.devmaster.net/wiki/Action).
Plus, even with the WikiMedia network of wikis (Wikipedia, Wiktionary, etc), there isn't even a unified logon, making it even more annoying trying to edit them all.
At any rate, I think the Game Programming Wiki and the DevMaster Wiki should merge.
There's one point in having multiple Wiki's though, if you're unsure if a particular piece of information in one of them is absolutely correct, you can quickly check the other one just to see if that particular information is supported there as well. That's just my opinion though.
Generally, sometimes slightly skewed information does sneak into those editable Wiki's even if a lot of effort is put into keeping them correct.
Well, that's what the article history is for. Besides, how many people are going to be monitoring multiple wikis to ensure accuracy vs. monitoring a single wiki? (Answer: not many.)
Wikipedia is encyclopedia and doesn't allow any original research, comments or guides or anything like that. You can't just compare these two, although I agree that some parts which are adequately documented in wikipedia could be left out from the devmaster wiki.
Actually, anything can be compared (for "compare" means similarity and difference). Wikipedia is full of original research, despite its conflicting/contradicting policies about it (and many other things).
The Dev Master, Game Programming, and other game development wikis don't need to waste articles explaining concepts when Wikipedia does a far better job. Instead, such topic-specific wikis can focus on "how-to" tutorials/guides, unreferenced original research, and deleted content from Wikipedia that is still relevant (like my "action (gaming)" article, despite having sources).
I'm experimenting with a wiki for my 3D Game Comparison and it will link extensively to Wikipedia for general info about games, companies, game features, etc (as the non-wiki site currently does). However, site-specific "articles" (more like categories and the comparison table) can stay on my separate wiki (for now; I'd rather have a single wiki for everything--including dictionary entries--but WikiMedia doesn't agree, unfortunately). I'm going to try using the Semantic MediaWiki extension (which isn't installed on Wikipedia, as far as I can tell) to get a more database-like system that auto-generates tables without actually having to deal with database design (at least as far as I understand what a semantic wiki is thus far--having only been exposed to it for a few hours now).