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Create groups to organize your subscribed users and send them e-mails based on their groups or by user levels, capabilities or usernames. You can also send messages for anybody, directly by e-mail addresses. Besides that, you can use some information of the current user and of a selected publication (post or page), to personalize the message, that can take attached files, if you want.
WPMailing offers support if you are using Xinha4WP or Dean's FCKEditor, to write e-mails in your favorite editor.