During the month of November 2011, Mozilla conducted a Thunderbird usage survey. The survey was available via link on the Mozilla Thunderbird Start Page. The results were quite interesting:

• More than 70% Thunderbird users are men! Please, tell your wife, daughter, partner how great Thunderbird is!
• Up to 90% of you use Firefox as a web browser.
• 65% of the respondents have 2 PCs or more and have Thunderbird on most of those PCs.
• +70% of respondents use either Instant Messaging or Social Network service. This is a slightly higher number than to ones measured in the industry (Forrester 2010: 68% of online Europeans now use social media each month.)

You can find out more at the Thunderbird Blog.