Email Usage

Question: How many emails are sent every day?
Answer: Statistics, extrapolations and counting by Radicati Group from August 2008 estimate the number of emails sent per day (in 2008) to be around 210 billion.
183 billion messages per day means more than 2 million emails are sent every second. About 70% to 72% of them might be spam and viruses. The genuine emails are sent by around 1.3 billion email users.

http://email.about.com/od/emailtrivia/f/emails_per_day.htm