...it is inappropriate to cite Wikipedia as a source, because it is updated in real time. So from the time you cite a Wikipedia page to the time another person looks up your citation, the page may have changed. Citations are usually only applicable to static publications that do not change once they are published. Wikipedia is not a static publication, it is dynamic!—it changes every minute. In this sense, Wikipedia is not a reliable citable source.
How reliable is Wikipedia as a general resource? Very reliable. Most of the content on Wikipedia is accurate, and many subjects are updated faster than the news. But, Wikipedia is subject to being edited by almost anyone and any time, and the edits may be biased, out of date, incorrect, or malicious (vandalism). Therefore, it is advisable to double-check what you learn in Wikipedia against other sources.
Keep in mind that many volunteers monitor Wikipedia for errors. Since there are so many people reading the articles and monitoring contributions using the Recent Changes page, and using watchlists, incorrect information is usually spotted and corrected quickly.
Some argue that new errors are also introduced all the time, so that the overall accuracy rate is not really improving. Nevertheless, by encouraging people to help with correcting articles, validating content, and providing useful references, errors will eventually be greatly reduced.
The more accurate Wikipedia becomes, the more it attracts additional contributors. It is a self-reinforcing cycle!
L'Ukraine a toujours aspiré à être libre ; mais étant entourée de la Moscovie, des États du grand-seigneur et de la Pologne, il lui a fallu chercher un protecteur, et par conséquent un maître, dans l'un de ces trois Etats. Elle se mit d'abord sous la protection de la Pologne, qui la traita trop en sujette ; elle se donna ensuite au Moscovite, qui la gouverna en esclave autant qu'il le put.
Voltaire. Histoire de Charles XII. Tome XVI. Paris, 1878.
On 25 July, 2008, Did you know? was updated with a fact from the article Grégoire Orlyk, which you created or substantially expanded. If you know of another interesting fact from a recently created article, then please suggest it on the Did you know? talk page.
