Spam accounts for 80 percent of unsolicited email marketing messages sent in North America and Europe, according to a new report from email services firm Responsys. According to the new report, "The New School Marketer’s Guide to E-Mail Deliverability," eight out of ten spam messages can be "traced via aliases, addresses, redirects, locations of servers and [domain name system] setups to a hard-core group of around 100 spam operations."