This is strictly a curiosity question, one I have wondered about many times.
Why doesn't DDO actively promote the wiki? I remember 2 or 3 years ago, for a brief period of time, there was some DDO advertising on the site.
Mostly though, why is it that there is no active support or mentions of the site from DDO staff? Why is there no official link anywhere on the forums to take players there? A lot of new player questions could be self answered if the site was mentioned more. I remember my beginning days on DDO, I would always try to answer my own questions via reading the forums, or even attempting the compendium (don't miss that thing at all).
Even though I saw posters linking things from the wiki, it was over a year of playing that it became my go to source for information, frankly I had to be berated in chat for my refusal to go there before I decided to go there and explore. Had I found any links, or even DDO staff posts in the forums recommending the use of the wiki, I probably wouldn't have needed the kick in the buttock region to start using it.
I still run into this issue to this day. New players I have helped out with some advice over time they still send me tells asking for help, and I understand now why I got the swift kick, I just cannot get some of these players to try the wiki. Now i don't mean this for every person I suggest to go to the wiki, I would say it is about 50/50 for those that do go there when it is suggested, and those that don't, but I think honorable mentions and maybe even a link on the DDO forums to take you right there would certainly be very helpful to new players trying to find their own information.
I still remember not wanting to appear foolish or ignorant on the game forums by asking simple questions that you just can't search out the answer for.
EDIT: For clarification, I don not mean to imply that I want Turbine to have so much as a single hair in the workings of DDOWiki, I mean support in the terms of advertising on the wiki, Advertising the wiki on the official site, and just helping the wiki to pay it's bills with the advertising so it is always a constant and reliable resource for us players.