I bought some BTC on Coinbase last night and had it sent to Poloniex. I know the BTC wallet address was accurate. Its still pending 11 hours later and doesn't show up in the Poloniex deposit/withdrawal history. Any clue on how long BTC transactions are taking?
The transaction time depends on its priority, and what you pay for each transaction speaks for itself. However, according to my understanding, coinbase always pays pretty high fees for transactions, if they have sent it, you will get notice in a short time. The only answer here is that they have not yet made that transaction.