I cant imagine drugs make up a significant portion of the BT economy, speculation/money transfers alone seems to account for most of it. I suppose the only way to know is if one of these drug sites go down and we see the impact on the trade volumes.
Yeah what is all this drug rep about on the news? It's like - how many drugs are being purchased everyday in USD? BOOM - A currency is harmless, it's the people that decide the future of it.