Actually while I dug around on Netflix website - I can across this "Fact Page" - which has some interesting notes about netflix.

They actually have 4 different price planes:
$13.95 Four DVDs a month, two (2) titles out at a time
$19.95 Unlimited DVDs, three (3) titles out at a time
$29.95 Unlimited DVDs, five (5) titles out at a time
$39.95 Unlimited DVDs, eight (8) titles out at a time

Plus they have 20 "shipping" centers around the US to try to make the mailing of DVD's be an overnight type thing - or close to it.

Plus If Netflix members, instead of receiving movies by mail, drove two miles each way to a rental store, they would consume 100,000 gallons of gasoline per day and release 300,000 tons of carbon dioxide emissions annually.

.... I have no idea why i'm trying to "pitch" this to people when I don't use it myself, but.... :-)