Buy milk, egg and flour
P.S. Anyone seen the player?

A blackboard is a memory are for AI related data that can be shared with the agents that care about it. It's now uncommon that a agent have access to more then one. For example a internal agent blackboard for all the parts of the code that run on the agent and a shared one where he can communicate events with other agents.

Unreal Engine: Blackboard Documentation - 2014
Blackboard Architectures, AIGPW1 p333-p344. - 2002.