Hi, there are no official figures as this is can only be determined on a per user basis. On many of the sites I manage they had the same concern but the increase wasnt even noticeable (e.g. a few MB extra per user per month for heavy users). Keep in mind most html content will only be formatted text and images in email signatures. When users receive a full html news letter it will only download the none imbedded content if you press the menu button and select Get Images.