Our domains had somehow gotten entered in pbl.spamhaus.com (see http://www.spamhaus.org/pbl for details). We think this is a result of authentication issues encountered while transitioning from Slicehost to Rackspace (Rackspace acquired Slicehost, our ISP). These have been addressed and we've submitted an update to spamhuas. Everything should be back to normal shortly.
Thank you for bringing this to our attention.
BTW, senderbase appears to have issues with their threat assessment. Per spamhaus:
"The first thing to know is: THE PBL IS NOT A BLACKLIST. You are not listed for spamming or for anything you have done. The PBL is simply a list of all of the world's dynamic IP space, i.e: IP ranges normally assigned to ISP broadband customers (DSL, DHCP, PPP, cable, dialup). It is perfectly normal for dynamic IP addresses to be listed on the PBL. In fact all dynamic IP addresses in the world should be on the PBL. Even static IPs which do not send mail should be listed in the PBL. "
That's nowhere near "Senderbase is blocking the site since it has exhibited highly suspicious activity and apparently by going to this site users are at high risk of getting infected with malware."
The spamhaus PBL was the only negative info on the senderbase list for us. You might want to contact their customer support, since it's likely they'll block other sites.
Edited by: pharsha on Jul 15, 2012 1:28 AM
Fusesource.com is now available and back in action