g1smd - 12:00 pm on Jun 20, 2011 (gmt 0)
It is the job of the server to accept URL requests and map those to folder and files inside the server and fetch the content. You can point any URL request at any piece of content.
Pointing multiple URLs at one piece of content leads to Duplicate Content problems. This has been an issue in the past, where Google would pick one URL to list in the SERPs, and it might not be the one that you wanted. The recommendation was to redirect non-canonical requests to the canonical URL.
Things are changing, even within the last few days: [webmasterworld.com...]