Complex sentence: Often when a user is banned, or a similar message is posted their user or talk pages, this is intended to replace those in order to welcome the user back and make it clear to one and all that the ban has been lifted.
Split into simpler sentences: Often when a user is banned, or a similar message is posted on their user page or user talk page. This is intended to replace to welcome back the user and make it clear that the ban has been lifted.