Email and web security vendor Barracuda Networks has released its annual spam report, in which it claims that between 90 and 95 percents of all email sent in the year 2007 was unsolicited. The company analyzed over a billion email messages sent to its 50,000 clients every day in preparing the report.
The majority of these messages used obfuscation techniques such as masking the senders' real addresses with known and trusted email addresses, or registering new domain names to defeat blacklists of spam sources. The usage of attachments such as PDF files to carry an advertising payload also increased, in the same way that image-based spam rose to prominence last year.
A related study of 261 business professionals found that 57 percent of respondents viewed spam as the worst from of junk advertising, more so than postal junk mail and telemarketing. While 50 percent received five or fewer spam emails each day, 13 percent reported receiving over 50 such messages each day.