I am working on an email program and I want to add a basic way to detect spam based on the domain/sender of the mail. One service that I was looking at was gossip (http://gossip-project.sourceforge.net/) but I don't want to go to the hassle of setting up a dedicated Gossip server. I know that there are a lot of email blacklists (DNSBL's) and stuff out there that can give you an estimate of whether or not an email is spam based on the domain it was sent from. I'm wondering if anyone knows of one that I can just query from within a program by passing it the sender's domain and having it return the likelihood that the email is spam. I don't want a service that requires me to set up a server for it.