Internet in Numbers (2008)
There are some v interesting numbers in this Pingdom article. A few highlights:

• 210 billion – The number of emails sent per day in 2008 (70% SPAM)
• 1,463,632,361 – The number of Internet users worldwide (June 2008)
• 133 million – The number of blogs on the Internet (as tracked by Technorati)
• 12.7 billion – The number of online videos watched by American Internet users in a month (November 2008)

I am not sure about the validity of the numbers but they sure give a sense of the order-of-magnitude.