I think Latishya has the key:

"A little learning is a dangerous thing;
Drink deep, or taste not the Pierian spring;
For shallow draughts intoxicate the brain
And drinking largely sobers us again."

http://en.wikipedia.org/wiki/Pierian_Spring

It could mean someone with a strong interest in the arts or it could have a derogatory implication, perhaps referring to a dabbler or someone with very superficial understanding.