You are looking probably for some DRM solution. Not really a Bus question but more a technical question. Could try stack over flow or just query DRM for CDs. The solution of having it log onto a web site would go counter to the nature of a physical CD but some games do use that as their DRM solution. Another possible method is you key each CD and when they input it in it logs the key into your system and checks for duplicates. There are many methods and I'm no expert on DRM. You may want to try your luck at StackOverlfow.
and welcome to this site! :-)
Unfortunately I think the technical aspects of your question fall outside the scope of this site. You're welcome to ask; but I doubt if you will get good answers. Who knows, maybe somebody will surprise me.
There is a slew of copy protection / DRM solutions for CDs, but AFAIK all of them can be circumvented by a determined hacker. And they often add annoyances for the users.
A very common solution today is to avoid CDs altogether, and go directly for streaming content over the Internet. With the right choice of player and usage monitoring, this offers a fair level of protection.
Product activation seems to be the most prevalent solution today since it allows companies to track the serial codes to specific customers -- with Microsoft/Adobe/Norton and other high end software companies having plenty of success with it, however I'm not sure about the costs of the logistics behind implementing that technology.
Despite the effectiveness -- there are plenty of instances where this type of DRM has caused studios to take major hits. Such as EA when they launched Spore and the backlash over the DRM was so bad, the game on Amazon.com had one star from +1k "customers" and people were boycotting EA, and in the end the matters were resolved.
On a side note, when Amazon retracted the negative reviews over Spore, they also had a major credibility backlash stirring debate over who decides if reviews are valid, but bottom line is that typically DRM will do more harm than good.