The ads are provided in two ways.  First, they are stored as PDF's, which are both easy to view as email attachments, and usable in some newsletter and brochure formats.)  The ads are also available in Indesign format, with included images and font outlines.  This is one format used by glossy magazines, for instance. Even when submitting an ad to a magazine, sending the PDF file along with the other files lets the recipient preview how the ad will look first.