Blocking out tens of thousands of commercial ranges goes a long way towards cutting spam down to reasonable levels, and blocking tens of thousands more of their residential (static and dynamic) addresses every week or so keeps them from making that approach profitable too. Of course, this filter works better and better with each additional ultrapeer that loads and uses it.

Each person that uses one enjoys a greater degree of freedom from spammers, fake files and even trojans, saving them a lot of time and frustration. More importantly, this large list effectively shuts out all of the huge server farms, saving the individual user a lot of wasted bandwidth.

BearShare has 160 of the worst bandwidth abusers blocked by default where LimeWire has precisely zero. I just might throw together such a short list and submit it to the developers to include with all future releases, since the biggest offenders rarely move their massive farms to new addresses.

Hosts filters are not the total solution to wasted bandwidth and spam but you haven't even started solving the problem until you do this first vital step. Once you knock off +90% of them, you can concentrate on the rest more effectively.

Keep an eye out for more of these filters. I expire and replace them frequently to stay ahead of these critters. They are named like "LimeWire.fullsize.hostiles.list.-.July.12.2005.-.(DELETE..ALL..PREVIOUS..LISTS!!!).zip" and always have a date on them. Search for zips named "Fullsize hostiles list" to find them. There are versions for BearShare and Shareaza too, and I'll add more servents as I learn how to accomodate them.

Remember, keyword filters are easy to sneak around with a little stroking of the keyboard but avoiding host filters takes a lot more intelligence, effort, time and money and spammers are notoriously stupid, lazy, impatient and cheap.