The fundamental principles of Wikipedia may be summarized in five "pillars":
A major difference between Wikipedia and other large reference resources is that Wikipedia articles can be edited by anyone. This can be seen as a strength and a weakness.
It benefits from vast numbers of volunteer contributors from all walks of life, facilitating the unprecedented depth and breadth of articles which can be updated as events evolve and change over time.
However this community aspect can also mean that entries are susceptible vandalism, bias and questionable quality and accuracy.
Wikipedia has a community of editors who review and keep articles up to date and accurate, but you should be aware of this key issue and critically assess and verify material that you find in Wikipedia.
Video published by Justin Franco on Dec 2, 2009.
This is a short video about how the online information repository Wikipedia came into being.