Isn't HTTPS disabled by default in Gmail (other than the login page)? This was definitely true about a year ago, if not today.
If so I would imagine 95+% of users aren't/weren't using HTTPS, making it trivial to read most of the population's Gmail.
Edit: I was wrong about "definitely true about a year ago", they turned HTTPS on by default in January 2010. http://gmailblog.blogspot.com/2010/01/default-https-access-f... . Seems reasonable that the government could only have been "packet tapping" before 2010.
If so I would imagine 95+% of users aren't/weren't using HTTPS, making it trivial to read most of the population's Gmail.
Edit: I was wrong about "definitely true about a year ago", they turned HTTPS on by default in January 2010. http://gmailblog.blogspot.com/2010/01/default-https-access-f... . Seems reasonable that the government could only have been "packet tapping" before 2010.