One notable strength of Wikipedia is its timeliness. Traditionally, new editions of encyclopedias were released every few decades, as their information became noticeably obsolete. The idea of continuous revision, in which the entire encyclopedia revised and reprinted every few years, replaced this and is now employed by most encyclopedias. Wikipedia takes continuous revision to its ultimate limit — almost all articles may undergo revision at any time, allowing the project to incorporate current events. For example, the article on the 2004 Indian Ocean earthquake in the English-language edition was cited frequently by the press in the days following the event.