List of possible tools

• see Andreas Hochsteger's list
  
• DocSynch - Plugin for JEdit, tests by Arje Cahn have shown that it requires exclusive locking of the document.
  
• Reduce - currently they provide a single "demo" account, trying to edit the same document from two different systems crashed the app, but this might be due to the same username being used twice. I have contacted them to find out – Bertrand Delacretaz.
  

(There was a table here, meant to compare tools but it was empty. If you need it you can get it back from version 1 of this page).