If you want to log the POP/IMAP/SMTP activities of Thunderbird email, you can:

http://email.about.com/od/mozillathunderbirdtips/qt/et_mail_log.htm

Log POP, IMAP and SMTP Traffic in Mozilla Thunderbird

To create a log file with all POP (Post Office Protocol), SMTP (Simple Mail Transfer Protocol) or IMAP (Internet Message Access Protocol) traffic in Mozilla Thunderbird:

• Make sure Mozilla Thunderbird is not running.

Now, on Windows:

• Select All Programs | Accessories | Command Prompt from the Start menu.
• Type "set NSPR_LOG_MODULES=" followed immediately by
  • "POP3:4" for POP,
  • "IMAP:4" for IMAP and
  • "SMTP:4" for SMTP
  logging.
• Press Enter.
  • You can enable logging for multiple protocols by separating them with commas (',').
  • To log both POP and SMTP traffic, for example, type
    

  • set NSPR_LOG_MODULES=POP3:4,SMTP:4

  • To log only IMAP traffic, type

  • set NSPR_LOG_MODULES=IMAP:4

• Type:

•  set NSPR_LOG_FILE=C:\temp\tbird_log.txt

• Press Enter.
• Type "start thunderbird".
• Press Enter again.
• Perform the desired email actions in Mozilla Thunderbird.
• Quit Mozilla Thunderbird and take a look at "tbird_log.txt" on your Desktop.