It still does, actually, but on a much shorter delay. If you make a market buy order with an online broker, it will execute pretty much instantly, but the price might have fluctuated between the time you pressed the button and the time the order was filled. It usually makes little difference, but people have ended up paying a lot more than they expected on some rare occasions.

This is common enough with ETFs that some brokers advise their clients to always use limit orders.