Fees and slow processing times clogging the market
Something you will be hearing more about in the weeks ahead is the 'mempool'. Simply, it's how many unconfirmed (unfinished) transactions are in the Bitcoin network.
The problem is that every transaction in Bitcoin is tracked in the ledger (the blockchain) so everyone needs to confirm every transaction. As more transactions take place, this is becoming increasingly difficult.
At the moment, there are 170,000 unconfirmed transactions and the average fee is $15 and even then, your transaction might take 12 hours to confirm. To get something through faster, you need to pay more.
It's gotten to the point, where the fees are turning off drug dealers. Here's a post on reddit in darknetmarkets.