Has anyone found out if they do anything other than light up? Or are they just some form of unreadable in game lore repository?
i have the same question...
AFAIK they are pure lore, no in-game effect. Hardly unreadable, though. I've started a theory thread here (spoiler warning).
There is an achievement for finding all of them. They also tell the story of where you are and how you got there. Their design is actually quite clever.