On a question I just answered, I noticed that they link to an external site where they've also posted the same question:
Regarding memory usage of Java Application
Initially, I was about to edit the question to remove the link, but saw a high rep user had already edited the question and left the link in - presumably because it's ok?
Is there any guidance for whether it's acceptable on SO/SE to ask the same question you've asked elsewhere and then link to it?
Is it better to keep the link in case the question is answered on either site or do we discourage linking to (competing?) non-SE sites?