Journal feature. How does it work?

The new Journal feature.

Does anyone knows how this feature work?

I'm tempted to use it, but I know not how it works.

Or it's intended use.

Exactly the same way like notes.

Do they keep over like 2 years?

Or do they disapear like notes do?

From my limited experience with them, I would say they don't disappear.

A journal should have some valuable content, either explaining a trait of the character, something that happened to them / they experienced that forms their character, their internal thoughts and reactions to something that happened to them, etc.

It definitely should not be something like I got up and brushed my teeth, killed 3 plasm beasts and gained one rank in my guild.

One of my toons leaves an entry on influential characters he meets.  But when something big happens or I think of something that happened to my char I leave one.  I actually did a bunch of notes when I first came back that could and should have been journals, but I really like the idea.

I call it a diary.

Yes, my toon very much treats his as a diary, I even have been known to talk to it on occasion in my entries.