2013 Job Descriptions for Fundraising
Carrier envelope: Its job is to get opened (and to hold the contents in place, but we'll assume that's a given). The only reason for a teaser on it is to increase the likelihood of it getting opened. The only reason not to use a teaser (or a photo or illustration) is to increase the likelihood of it getting opened. Would someone who isn't your colleague or your mother actually open that envelope? If not, it's failed in its job.