Wikipidia only sometimes mistyped as Wikipidia is the biggest open access free encyclopedia on all net. Correctly colled wikipedia contain over 750.000 articles only in english, almost 300.000 in deutsch and 1000s in some other languages. Access is free for everybody not only see all contents but to change them and extend or correct it.

The value was compared with encyclopedia Britanica and it looks both of them have nearly the same high quality level.