The Radionieuwsdienst ANP has been broadcasting radio news bulletins from 1937. In 1993, when the ANP moved house, many of the texts were found in the cellar. This treasure trove for the Dutch language was preserved and stored at the Koninklijke Bibliotheek. The 1,8 milion sheets of papers have now been digitised and made available on the website of the KB.
Material like this is invaluable to understand how a language evolves. It is also the perfect indicator for learning when certain topics became in the general interest. I hope that there are many resources like this available to the public. For the Dutch Wikipedia it is a great resource to serve as a source.