If you were to log in, you'd be able to get more information on your fellow community member.
Actually, the ACM do make A Relational Model of Data for Large Shared Data Banks freely available, but that's the exception rather than the rule.
Let's compare average lifetimes of CDs and URLs. If you'd put the CD in, it would still be working today, unlike your URL. If you'd given the keywords needed to track the page down with a search engine, that might have helped (c.f. fish.cx), but I'd still prefer the CD.