On August 1st, 2005 CWoT opened its doors to the public on its very own domain. To celebrate the 15 years of CWoT, ACWoT provides you with the crystal side quest. Since crystal is the 15th anniversary gift, it is only fitting.
This side quest doesn't deal with the original game much at all. You aren't required to have past knowledge of the old site or riddle. However, each level will have something to do with anniversaries, the number 15, crystals or a mixture of all of the above.
When you get stuck you can turn to the Member Forum for help, clues and general assistance.
Good luck, and have fun!