Thunderbird: Guide for the Perplexed

What Is Thunderbird

Open souce crossplatform mailer created as a redesign of the mailer component of Mozilla Suite (known now as SeaMonkey) using Gecko layout engine
Wikipedia: Thunderbird, history of Thunderbird, comparison of mailers
Abbreviation: Tb
Motto (?): Reclaim your inbox
Images: buttons, logos
Good companion to Firefox

Profile folder
Important files in the profile folder:
- abook.mab: personal address book
- prefs.js: preferences

List of preferences
// Display both time and date of today's messages
user_pref("mail.ui.display.dateformat.today", 2);
// Force HTML messages to be displayed as plain text
user_pref("mail.default_html_action", 1);
// Disable plain text tags
user_pref("mail.display_struct", false);
user_pref("mail.send_struct", false);
// Disable graphical style of quoting
user_pref("mail.quoted_graphical", false);
user_pref("mail.quoteasblock", false);
// Disable format=flowed
user_pref("mailnews.display.disable_format_flowed_support", true);
user_pref("mailnews.send_plaintext_flowed", false);
// Show the user agent in the message header
user_pref("mailnews.headers.showUserAgent", true);
// Change default paper size from US-Letter to A4
user_pref("print.postscript.paper_size", "A4");

/* Change the font weight of account names on the folders pane from bold to normal */
treechildren:-moz-tree-cell-text(folderNameCol, isServer-true) {font-weight: normal !important; }
/* Change the font weight of subfolders with unread messages from bold to normal */
treechildren:-moz-tree-cell-text(hasUnreadMessages-true) {font-weight: normal !important; }
/* Change the line height of the header to, e.g., 1.25 em */
.headerName {margin: 0 !important; line-height: 1.25em !important; }
.headerValue {margin: 0 !important; line-height: 1.25em !important; }
.headerValueBox {margin: 0 !important; line-height: 1.25em !important; }
/* Change the font weight of the value of the subject line in a message header from bold to normal */
.subjectvalue {font-weight: normal !important; }

/* Leave the margin of, e.g., 0.75em in the message pane */
body {margin: 1.25em !important; }
/* Change the line height of a message body to, e.g., 1.25em */
body {line-height: 1.25em !important; }
/* Disable horizontal bars beside quoted texts */
blockquote[type=cite] {padding: 0 !important; border: 0 !important; }

Display HTML messages as plain text:
View -> Message Body As -> click "Plain Text"
Compose messages in plain text format:
Tools -> Account Settings -> Composition & Addressing -> Composition -> uncheck "Compose messages in HTML format
Start your reply below the quote:
Tools -> Account Settings -> Composition & Addressing -> Composition -> check "Automatically quote the original message when replying" and choose "Then, start my reply below the quote"
Disable the display of emoticons as graphics:
Tools -> Options -> Display -> Formatting -> Plain Text Messages -> uncheck "Display emoticons as graphics"
Use monospace fonts:
Tools -> Options -> Display -> Formatting -> Plain Text Messages -> check "Fixed width font"
Minimum font size:
Tools -> Options -> Display -> Fonts -> set "Minimum font size" for each character set
Default character encoding:
Tools -> Options -> Display -> Fonts -> Languages; choose a character encoding from the drop-down menu
Block loading of remote images:
Tools -> Options -> Privacy -> General -> check "Block loading of remote images in mail messages"
Software update
Global inbox
Saved search folders
Message grouping
RSS news & blogs

Include a server when getting new mail:
Tools -> Account Settings -> <server> -> Server Settings -> Advances -> check "Include this server when getting new mail"

Thunderbird Add-ons: Extensions [annotated list of extensions] (feed)
Local Install [extension for installing extensions and themes from a local disk and enabling incompatible ones]
Folderpane Tools [extension for customizing the folder pane]
ReminderFox [light-weight calendar extension]
FoxClocks [world clock extension]
Quicktext [extension for adding precomposed texts (e.g., signatures) in the compose window]
Buttons [various toolbar buttons]
Empty Trash [toolbar buttons for "Empty Trash" and "Compact Folders"]
Rewrap Toolbar Button [toolbar button for "Rewrap"]
BiDi Mail UI [extension for right-aligning plain text messages]
Transliterator [extension for transliterating Cyrillic and some other non-Roman scripts used for Russian, etc. with a US English or any other Roman-script keyboard]
Dictionaries [dictionaries for the spell checker in various languages]