This question already has an answer here:
If a site uses content originating from a Stack Exchange site, is the user who owns the content legally permitted to make his post "native" to the non-SE site?
Here's what I mean. Some non-Stack Exchange site uses a post originating from an SE site, with all required attribution. The post was posted on SE by user X. If user X registers on the non-SE site, is the user allowed to remove the attribution and make it native to that site?
It should be, because it is the user's original content, but I just wanted to verify that this is legal.
Note that no such incident has actually occurred! It is just a hypothetical situation which came to my mind...