NOTE: This is outdated information that applies only to Tapestry 4. For current information see http://tapestry.apache.org/ioc.html.
HiveMind is a services and configuration micro-kernel used by Tapestry 4. It was an outgrowth of work on Tapestry 3. Tapestry does a lot of object creation and configuration. HiveMind was a re-invention of much of what Tapestry 3 did, but in a generic, non-web based, highly reusable form.
Tapestry4 made heavy use of HiveMind, deprecating and removing much of the infrastructure and reinventing it as HiveMind services and configurations. This made it much easier to extend the behavior of Tapestry without having to subclass BaseEngine.
As of Tapestry 5.0, Hivemind has been replaced by a new inversion of control layer called Tapestry IoC.