Wikipedia

The Wikipedia Scanner was created by Virgil Griffith. By tracing IP adresses, it informs people on changes made to Wikipedia. This device can let you know who edited the article and when they edited it. This is a neat device. It is obvious that Wikipedia shouldn't be used as a reliable source because anyone can edit the information. With the Wikipedia Scanner, you know who has been editing.
I think this would be a good activity to use in the classroom. To show the students how important it is to make sure they're using reliable sources, a teacher could use the Wikipedia scanner and trace any article from Wikipedia to show the students how anybody can edit those articles.