The original AC 0.93 Ladder was created by Acfan, member of the TearYouDown! clan. Unfortunately, the server running this Ladder crashed, and his server hasn't been back since. Since two of KanslozeClown's servers (Clown and Krusty) were already calculating stats for the Ladder, these data has been used to create a new Ladder which contains scores from these servers, as well as those from a third server: Pennywise.
The AC 1.0 ladder was created by KanslozeClown, several changes where made to support the new servers and game modes. Due to the release of AC 1.1, the old ladder has stopped on August 10. The final results from the 1.0 ladder can be found here.
The AC 1.1 Ladder have been updated by pwnage, to support the new logging and scoring events. Also, the public servers hosted by TyD!, jamz and MaxFrags provide stats for the ladder now. If you want to contribute with a server, make sure to read the requirements thread here.
Any questions, suggestions and bugreports can be sent in a message on Tear You Down forums, or visiting the #tearyoudown channel at GameSurge.