"Eventually, he plans to set up mirrors, but he'd like to get the greedy users under control first. Alternatives are adding a (free) log-in authentication system, or a text-in-image system like Network Solutions uses to weed out automated whois queries. But I think the best solution is to allow a given client IP address full-speed downloading for the first $WHATEVER megabytes, and then automatically reduce the speed of the transfer to that IP address. This would probably deter most leeches but continue to allow legitimate users to transfer more than an arbitrary limit."
BigBlockMopar asks: "A friend of mine runs a web site which offers a very large archive of files. He wishes to continue to offer free and unrestricted access to his archive, but his bandwidth consumption has been through the roof because of people using wget (and similar) to download his entire site. Current traffic is around 200 gigabytes per month with over 50% of that being clients who are downloading every document on the site. The server space is donated by a hosting provider who is understandably starting to become impatient with the traffic. I've checked out mod_throttle and mod_bandwidth, neither appears to do exactly what is desired. Does anyone have any suggestions?"