I did, too! And it reminded me of a project idea I had a while ago:

A time traveller's wiki that collects casual knowledge for different times (and different places).

Such as: "Buying a train ticket in Paris in 1972".

But it was a shower thought and it's pretty hard to imagine how this knowledge should be collected and especially presented.

In a way, wikipedia is already doing this by keeping records of articles as they change over the years :)

The article about train tickets wasn't so good as an example but "computer monitor" from 2004 is kind of fun to read :)

Unfortunately, "casual knowledge" is often omitted when writing informative articles. In this example, there is no mention that power buttons are often located somewhere in the back of the monitor, which was good to know in 2004. Also, some monitors are drawing power from the computer, thus they won't power up before the computer will. And speaking of that: You may want to turn of your computer after shutdown!

Edit: This would probably be useful for novelists and filmmakers (in addition to the casual time traveller)