Netdoc has switched from Turck MMCache to eAccelerator.
Turck MMCache is a great product but unfortunately it is not maintained anymore. However, there is a group of motivated developers now behind the successor of Turck MMCache, and the project is called eAccelerator. Netdoc requires eAccelerator, and eA is included in the Netdoc package as well.
Linux users have to compile eA themselves, for Windows users there are eAccelerator binaries.