Deletionpedia archives Wikipedia articles when the are deleted—a regular occurrence given how tightly "the free encyclopedia that anyone can edit" is policed by the insiders who edit the edits (previously, previously). [deletionpedia.org via Hacker News]
Deletionpedia is a radical inclusionist wiki for rescuing articles that have been discussed from Wikipedia's deletionism. It was started by Guaka on December 24th 2013 and so far we've rescued 91,250 articles.
More reading: Gwern In Defense of Inclusionism.
Wikipedia is declining, fundamentally, because of its increasingly narrow attitude as to what are acceptable topics and to what depth those topics can be explored, combined with a narrowed attitude as to what are acceptable sources, where academic & media coverage trumps any consideration of other factors. This discourages contributors—the prerequisite for any content whatsoever—and cuts off growth; perversely, the lack of contributors becomes its own excuse for discouraging more contribution (since who will maintain it?), a self-fulfilling norm (we focus on quality over quantity here!) and drives away those with dissenting views, since unsurprisingly those who advocate more content tend to also contribute content and be driven away when their content is. One bad editor can destroy in seconds what took many years to create. The inclusionists founded Wikipedia, but the deletionists froze it.