Badgermushroom said: "so if I see a file which has a reasonable file size for what it claims to be, and has say 5 identical files, then am I likely to have 5 sources for it? Or are 4 of them likely still to be spam?"
This would be OK You could not have spam grouped together with a good file (afaik
)
As for filtering spam (and viruses) ... let's just say it's been worked on, either as a e-mail type spam filter or a size filter ... which has been discussed most recently in
http://www.gnutellaforums.com/showth...ize+and+filter
which might interest you.