What counts as "canon"?

[Nogrod]

I kind of share Skip's uneasiness with the newspaper in Bilbo's hand. I mean, if there were newspapers in such a "backward" place as Hobbitton there should be yellow press in Minas Tirith! Just think of the headlines!

Or, from the printing press a typewriter is not so far away...

But:

Originally Posted by Lalwendë

Though I have to say that maybe attaching real historical periods to different cultures in Tolkien's world is maybe not advisable in general, it being a fantasy world and all that.

This is very true. Even if one is compelled to join certain discoveries to others as it would be "natural" to do so. And maybe just because of that.