Keyword Analysis & Research: why is blackboard called blackboard

Keyword Analysis

Keyword	CPC	PCC	Volume	Score	Length of keyword
why is blackboard called blackboard	0.68	0.8	6112	45	35
why	0.73	0.3	3646	91	3
is	1.86	0.1	4143	48	2
blackboard	1.23	0.1	6467	33	10
called	0.82	0.2	8024	27	6
blackboard	1.09	0.3	1503	58	10

Keyword	CPC	PCC	Volume	Score
why is blackboard called blackboard	0.73	0.8	8637	62