--- a/thunderbird.rst	Tue May 05 17:15:57 2009 +0300
+++ b/thunderbird.rst	Thu May 07 12:50:06 2009 +0300
@@ -14,3 +14,43 @@
 the full name, use the Config Editor to change the value of the preference
 mail.server.default.abbreviate to false.
 
+* Locate your profile folder.
+
+xxxxxxxx is a random string of 8 characters.
+
+ - %AppData%\Thunderbird\Profiles\xxxxxxxx.default\
+                Windows
+ - C:\Documents and Settings\[User Name]\Application Data\Thunderbird\Profiles
+                Windows XP/2000
+ - C:\users\[User Name]\AppData\Roaming\Thunderbird\Profiles\
+                Windows Vista
+ - C:\WINDOWS\Application Data\Thunderbird\Profiles\xxxxxxxx.default\
+                Windows 95/98/Me
+ -  ~/.thunderbird/xxxxxxxx.default/
+    ~/.mozilla-thunderbird/xxxxxxxx.default/
+                Linux
+ - ~/Library/Thunderbird/Profiles/xxxxxxxx.default/
+                Mac OS X
+
+* Customization.
+
+
+These files do not exist by default, so you need to create it before you can
+start adding your preferences:
+
+  <profile-dir>/chrome/userChrome.css
+  <profile-dir>/chrome/userContent.css
+  <profile-dir>/user.js
+
+** userChrome.css
+
+This file sets the display rules for various elements in the Thunderbird user
+interface.
+
+** userContent.css
+
+Thqis file sets the display rules for web content.
+
+** user.js
+
+This is the additional preferences file for Thunderbird.