This article will not try to describe the whole Wikimedia galaxy. It will stick to Wikipedia in English, and that's ambitious enough. The English-language Wikipedia, by far the biggest of them, now (28th November 2006) contains 1,506,659 articles. The German Wikipedia reached 500,000 articles on 23rd November (note in passing: the English Wikipedia has added that many articles to its total in just six months), while the French Wikipedia reached the 400,000 milestone on 27th November. The newest and smallest Wikipedia, number 250, is in the Lak language of Dagestan, in the Caucasus, with one article and 20 users.
One more statistical measure will show how much Wikipedia matters. People who Google already know that for a great many Google searches one or more Wikipedia entries will turn up high on the first page of the results. They don't all know that Wikipedia now comes eleventh in alexa.com's traffic ranking of world websites. For a strictly non-commercial site with relatively academic content, that is astonishing success; what's more, the trend is steadily upwards, though it will be hard to overtake the top four: yahoo.com, msn.com, google.com, and the highly popular Chinese search engine, baidu.com.