Spamhaus don't block anything? What a load of....
Spamhaus are a bunch of self righteous tw*ts.
I have had numerous run-ins with them over the years and they have never failed to treat me with contempt and always leave me feeling like I want to smash someones pathetic face in.
I don't spam... in fact I hate spammers, but they don't seem to want to help the situation at all and they are downright obnoxious.
And at the very end of it they sit back and say "we aren't block your mail, play by our rules or go away".
Unfortunately LOTS AND LOTS of people around the world use Spamhaus whether they like it or not because some administrator has decided to subscribe to the Spamhaus feed and treat it as gospel.
Which means when they block your IP.... expect to see at least 40-50% reduction in message delivery, if not more.
I know for a fact that they are all evil b*stards because they once blocked a large international house hold name Charities e-mail server during a large campaign relating to a recent humanitarian disaster. I won't go into specifics but it wasn't the charities fault and it took something like 4 weeks before they finally removed the block.