The sites art policy is at the very bottom of the page in the footer. However, that primarily applies to commercial endeavors. I'm quite certain no one here cares whether or not you use a map here for personal gaming. Its when you take someones map and try to claim it as your own or publish it or sell it that people start getting offended.
As for linking to the site...yes by all means link to us...I of course encourage it. But we're more a map discussion site than a map share site. Granted there's a lot of sharing going on here, but the primary focus is "how can I make my maps better" as opposed to "hey look at my map"