Spam
email accounted for between 90 and 95 per cent of all email in 2007, up from
an estimated five per cent of email in 2001, according to a report from web
security company Barracuda Networks. The report, which analysed more than one
billion daily email messages sent to more than 50,000 users worldwide, also
tracked the increasing complexity of spam techniques over the past several
years. 2007 witnessed the majority of spammers using identity obfuscation
techniques, in which spammers send email from diverse sources throughout the
internet. Other spamming trends also include the increased the use of
attachments, including as PDF files and other file formats.