This CNET article discusses the poor response of online customer service. Only one third of the companies surveyed in this article send automatic e-mails in response to your customer service request -- this is pretty sad, considering how easy it is to set up an automatic e-mail responder.
But an automatic responder is no big deal if the company isn't going to actually answer your question; thirty-two percent of the companies surveyed took 3 days or longer to respond! The lesson here: unless you can afford to wait a few days, find that toll-free customer service line and use it.