Just how heated has trading in Apple (AAPL +3.8%) become? With 50.6M shares changing hands today, Apple's dollar volume was roughly $30B. For perspective, the entire NYSE has seen an average daily dollar volume of $36.6B in February. Powershares QQQ (NASDAQ:QQQ), the ticker with today's second-highest dollar volume, only saw $4B worth of trades. (earlier)