Wikipedia is more comprehensive now than in 2008, but I speculate that its average article quality might be lower, because of (1) competent editors being spread more thinly, and (2) the gradual entrenchment of a hierarchy of Wikipedia bureaucrats who compensate for a lack of expertise with pedantry and rules lawyering. (I may be being unfair here? I'm going by faint memories of articles I've read, and my mental stereotype of Wikipedia, which I haven't edited regularly in years.)

This was in fact prior to 2008 (my advisor asked me to change something in the Bayesian network article, and I got into a slight edit war with the resident bridge troll who knew a lot less than me, but had more time and whose first reflex was to just blindly undo any edits. These sorts of issues with Wikipedia are very well documented). ---------------------------------------- The horrible article on confounders is another good example. I brought it up before here, and got the "that's like, your opinion" kind of reply. At least they cite Tyler's paper with me now! Of course, this particular case might be more widespread than just Wikipedia, and might be a general confusion in statistics as a field. I went to a talk last week where someone just got this wrong in their talk (and presumably in their research). ---------------------------------------- I don't doubt that there are isolated communities within Wikipedia that generate good content. For example, I know there are Wikipedia articles for some areas of mathematics of shockingly high quality. My point is, when this happens it is a sort of happy cultural accident that is happening in spite of, not because of, the Wikipedia editing model. ---------------------------------------- There has been quite a bit of experimentation online to incentivize experts to talk and non-experts to shut up, recently. I think that's great!