I don't think it's fair to say you work every hour of those hours, as you're here talking. It's probably more a case of how you're inside at the computer or something, where distractions await at every website.
When I do any form of advertising, I'm in the same boat. Just basically stuck waiting to anwer the phone, as I need to be in front of a computer. I did buy a PDA/Phone so I can get e-mails on the go, so my office is becoming pretty mobile. Laptop, phone, wallet. All I need to work anywhere.
But I often feel the same as you with working hours, but on reflection it isn't straight working like that. I have literally worked 22 hour days on really good programming projects, but generally I wouldn't do above 16. Plus the damn BBC website, if I monitored it, probablys accounts for an hour of that time.