Publishedon, createdon

Correct me if I’m wrong:

publishedon - the time, when doc should start applear at the frontend (is published)
createdon - the time when the Save button was pressed for the first time

pub_date - what’s this? Why is it sometimes 0 sometimes a valid timestamp?
publishedby - here should be an author specified, shouldn’t be? But why here is sometimes an author id, but sometimes a timestamp?
editedon - =1 in some rare cases...

Can anyone give me some info about how this works???

It’s all a mess. Please see the current Trunk for fixes committed to the save_content.processor.php ... there may need to be more made.