I went to five or six of the Websites of the vendors listed in the ad and searched for a mention of PrintTalk. I couldn't find one.
The ad for PrintTalk lists a Web site—www.PrintTalk.org. There I learned that PrintTalk "is a community formed by print management systems and e-commerce companies to define a 'best practice,' common and open communications interface (sic) between their products. The PrintTalk implementation will support use of the broadly published, proposed Job Definition Format (JDF) standard and Commercial eXtensible Markup Language (cXML). As part of the group's activities, it will seek to have its work recognized as an implementation of the proposed JDF standard. The PrintTalk interface specification will be distributed free of any license fees or royalties, in order to address the need for end-to-end connectivity in the printing industry. NPES serves as secretariat to PrintTalk."