I am saving my notes in a folder I share with my notebook through dropbox.
However, it does not work 100%: if, vg., I create a book and write some notes, the structure gets updated in the other notebook, but not the whole contents of its pages.
Could it be that both instances of kjots (pc and notebook) are not only reading from the file but also writing to it even if I am not doing anything to one of them?

Hola Carlos,
I am facing the same Problems throughout the whole Kontact Suite. It´s simply because of akonadi working in the Background you cannot share any data between multiple Computers. It´s all local - and this is not really the big Thing. Nobody knows where the data is stored. It is very very difficult to even backup the data. I can tell you an experience I had with KJots: On my PC I wrote something on page one of book one. The notes-folder was situated on a Server fully accessible by all Computers in my house. Now when I openend the page on a second Computer with a file Manager the page was there - I could even read it. However, when I opened the page with KJots on the second Computer - it vanishes!!! It is even deleted!!! Afterwards even with a file Manager you cannot find the page anymore. IT IS LOST FOREVER.
Saludos a todos.