Okay, I know you can set any URL you want on the Article, i.e. "MickeyMouse", but I don't understand at all what the prefix to that URL you set will be. How do you know? Will it be:
www.myorganization.force.com/MickeyMouse
?
Any help appreciated.
The Url will generaly point towards your Salesforce instance
https://yourInstance.salesforce.com
for Ex. A recent dev org, will have https://na40.salesforce.com/articles/language/articleUrl
if you have a custom domain enabled, you will see https://yourcustomdomainname.force.com/articles/language/articleUrl
You can find details on Salesforce Url changes here