+- DB_DataObject http://pear.php.net/package/DB_DataObject
+- Validate http://pear.php.net/package/Validate
+- XMLWriter (built-in)
+- Auth_Yadis from OpenIDEnabled (not the PEAR version!). I decided
+ to use the openidenabled.com version since it's more widely
+ implemented, seems to be better supported, and it may make sense to
+ use the openidenabled.com libraries for OpenID auth sometime in the
+ future. Note that this is no longer distributed separately; it's only
+ in the openidenabled.com OpenID PHP tarball.
+ http://openidenabled.com/php-openid/
+- OAuth.php from http://oauth.googlecode.com/svn/code/php/
+- markdown.php from http://michelf.com/projects/php-markdown/
+