The Channel 4 News revelations come in the wake of a civil servant losing his job over slurs added to the Wikipedia entry of Hillsborough and Liverpool FC, revealed by the Liverpool Echo earlier this year.
The changes have all come to light because anyone can check the history of a Wikipedia page and find what has been changed and when.
In some cases you can see which internet addresses has made the change and sometimes get a rough idea of who made the change.
In this quiz, you can test your ability to detect changes made from computers in the UK and US governments.