by Kirill Popov and Loren McDonald

If overzealous ISP and corporate spam filters don't cause enough stress for permission-based e-mail marketers, now we must deal with blocked images almost universally. In e-mail clients that block images by default, such as Outlook 2003, a recipient can read an entire column (such as this one) either in the message preview pane or when it's opened. The image-based ads and our dashing photo won't appear (nor will the message be counted as opened). For publishers, advertisers, and e-tailers, this isn't just a nuisance. It's potentially costly.