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 | This page in a nutshell: If you need to prove who did what where and when, it's essential to provide diffs as evidence. |
"So the next time an editor, or anybody else, urges you to "talk about indeffing", I urge you to reply "Shut up and show them the diff."
(with apologies to Eric S Raymond[1])
"I'm from Missouri. You have got to show me."
Wikipedia keeps a record of everything (more or less), and it can all be accessed by judicious use of diffs, which provide a link to a specific change at a specific point in time. The reason a diff is so important is it provides a comprehensive set of changes to an article by a specific user, at a specific time, with the edit summary they used. In other words, it shows exactly who changed what in an article, and is a smoking gun that easily clarifies things.