The teachers at my children's schools often use Publisher to create newsletters and notes to send to parents. As schools try to cut paper use, teachers and coaches are opting to email these types of files to parents. Sure, they could put the note within the body of the message, but then it wouldn't look like a newsletter or sport cool graphics supporting the school's athletics.
Not every parent's computer is equipped to view Publisher files, however, so I am often asked by teachers and coaches to convert their files to Adobe Acrobat's .pdf format. I could send them links to places on the Web to convert Publisher's .pub files into Adobe Acrobat's .pdf files, but the independent school district's network doesn't always allow employees to access these sites or applications.
Nevertheless, the Internet does offer a few free options for converting .pub files to .pdf. And converting Publisher files to PDF certainly makes sense in business environments, as most every company or organization's computers are equipped to handle PDF files.