Wikipedia is a free, web-based and collaborative multilingual encyclopedia project supported by the non-profit Wikimedia Foundation. Its name is a portmanteau of the words wiki (a technology for creating collaborative websites, from the Hawaiian word wiki, meaning "quick") and encyclopedia. Wikipedia's 13 million articles (3 million in English) have been written collaboratively by volunteers around the world, and almost all of its articles can be edited by anyone who can access the Wikipedia website. Launched in 2001 by Jimmy Wales and Larry Sanger, it is currently the largest and most popular general reference work on the Internet.
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Wikipedia is a fantatsic tool if used correctly by someone who knows how to decipher information and be critcal analysts. I have used it on many occasions to seek information or definitions of particular words. I think it is a very valuable tool and if used correctly within a classroom environment students will benfit from it. I do believe however that more problems that not will arise with incorporating this into a classroom context. Due to the fact that information can be added by anyone, it therefore means that the information is not always going to be reliable. I feel that although I have used this tool myself on previous occasions that I would more than likely shy away from it when I have my own classroom as dictionaries and other similiar resources such as books etc are more reliable and easier to navigate and decipher what information is right and wrong.