According to Commtouch Software, an average of about 10 million zombie computers worldwide are sending an average of 3 million messages every day. Some time periods indicate a collective peak spam output of 8 million to 10 million messages.
Many of those messages are sent through the top three web-based mail services. Gmail, operated by Google, ranks #3 among the top 10 origins for spam. Yahoo ranks #6, and Hotmail, operated by Microsoft, ranks #7. It's probably not coincidental that the rankings correspond to the popularity of each company's search engines and other online services.
The current top 2 offending domains origins are nearly unheard of by the majority of Internet users. Active-encounter.com, operated by marketing company iLead Media, ranks #1 and authentic-mechanic.com, registered to Tad Asaro, ranks #2. Asaro is registrant of the relatively new BabytoBee.com site.
Commtouch's cost calculator currently indicates that a company with 50 employees, each with an average salary of $50,000 per year, who also receive 25 messages per day - half of which are spam - would spent $14,300 per year as a direct result of dealing with spam.