Editors that create articles (with VE, wikitext, CX or any other tool), would appreciate knowing that their article was translated to a new language. That will motivate users to keep editing and make them aware of the existence of Content Translation.

Considerations:

• The Notification system (Echo) should be used in a way that these notifications get bundled in order to avoid them to be annoying ("The article X you started has been translated to 12 new languages" is preferred than getting 12 separate notifications).
• We want to analyse how many "chained" translations happened in CX (article translating from A to B, and later to C)