There are newer versions of Hamster. Ok, tell me the negatives. If your ISP does not carry them check out this free server. There are other sources on the net if you search. Local means it runs on your machine.
Hamster does the connecting to the Internet.
Gravity connects to Hamster like any other server. It can connect to another news server, or multiple servers, and pull in articles. Mail works the same way. You can connect to multiple mail servers and distribute the incoming mail or too newsgroups. You can then apply Gravity's rules and scoring to the mail.