A question for your consideration:
In a world where written text has magical properties, what are the implications of the invention of a printing press?
And now, for some related tangents to fuel the fire.
Some historical societies believed written words had certain magical powers. One example that springs to mind are Norse and Gothic runes, the name “rune” itself meaning “secret”. Inscribing runes on objects could act as a charm or a curse. Writing was Serious Business. However, I’ll be quick to note that runic script was also used for much more mundane affairs, and even in the pre-Christian era its use was more widespread than once thought. Even runes weren’t quite so sacred to avoid appearing as bathroom graffiti. And, of course, runic script continued on as a writing system well into late Middle Ages after losing all that pagan baggage.
There’s more to ponder here in regards to the pre-modern world, where reading out loud was the primary means of understanding a text. That is, reading silently was unusual, the written text was a delivery system by which you spoke out the words and then understood them. In the Middle Ages, reading in your head was a sign of unusual intelligence—this isn’t knocking on pre-modern people, of course, it was simply a different way of experiencing text.
If we follow a “rule of names” form of magic (such as in Ursula K. Le Guin’s Earthsea series), where knowing the true name of something gives you power over it, or any old belief that saying a curse or spell has its effect through the power of the words themselves, texts would become very dangerous indeed. Let’s say reading off a spell “unlocks” it from the words: the simple act of reading could cause significant problems if you stumbled across a harmful spell. The ruling elite would have to go to even further lengths to control literacy and the production of texts than was true in our own history (assuming they could), and we could imagine vast libraries of spells kept under lock and key. The introduction of a printing press would mark a devastating upheaval in the social order if manipulated by the wrong—or right—hands, by democratizing magic hitherto manageably controlled through the difficulty of reproducing texts.
As an exaggerated version of the printing press’s impact on Renaissance Europe, I think it could work rather well. Either situation presents interesting opportunities for mass chaos delivered by a fairly simple innovation.