Link: http://news.bbc.co.uk/2/hi/technology/5219554.stm
Some statistics from a report by 'email security firm' Return Path;
- 95% of all email is junk (spam, viruses, error messages) - Less than 4% is legitimate traffic - 99% of the computers they 'monitor' have been taken over by spammers - Only 1% of net addresses could be regarded as legitimate sources of mail. The rest are hijacked computers, or bots, used by spammers to send e-mail
Another company 'Ironport' claims that 80% of email comes from compromised hosts.