At the moment, as far as I understand it, only the owners (that is, whoever bought the item) are able to write in their own journal and scrolls. If you want a work to have multiple authors, you'd have to use a manuscript.
Would people like a system where you could bestow a journal to someone else and change ownership?
I suppose it would work similarly to mounts - they're yours and you can get them to follow other people (you can still GIVE JOURNAL TO X and they can read and not write, feed to a humgii, sell off, whatever) or you can choose to hand it over and make it theirs.
It could list previous owners. It could keep previous owner's written pages uneditable. If it is editable, it could show it on the page itself ("This page has been changed/corrected by NewOwner"). Maybe it can only be done the once - OldOwner to OnlyNewOwner.
Edit: As @Anaidiana
pointed out - you could buy journals for other people on the get go:
BUY JOURNAL/SCROLL [from denizen] FOR PERSON and it would be carried off by dove to them immediately. I presume this would make them the original owner, bypassing yourself possibly?