"Journalism" is a travel journal tool, for creating, managing and trading map notes. It was also the second addon written in closed beta, so it has a bit of a history to it!
To use, you can type '/jadd' in the chatbox to get a window where you can enter a title and some notes for your current location. If you do '/jadd Favorite Picnic Spot' then it will just create the note for you with that title, without bringing up the window. If you have a unit selected in the world and do /jadd, the location of the unit will used for the map note, and the title will default to the name of the unit.
Typing '/journal' in the chatbox will bring up the journal edit window. You can toggle minimap and zone map indicators on and off in that window, as well as add a new entry (just like typing '/jadd' alone), or edit/delete/share an existing entry.
Notes are shared among all characters on an account, though it does remember which character created the note. Notes can also be traded among players, though (at present) this is only one-at-a-time. Behind the scenes, it does support receiving multiple notes, so when the journal window is prettier and allows multiple selection, that'll work properly.
The forum thread for Journalism can be found here.