This is PGA’s wording for providing the credit:
A transmedia narrative project or franchise must consist of three (or more) narrative storylines existing within the same fictional universe on any of the following platforms: film, television, short film, broadband, publishing, comics, animation, mobile, special venues, dvd/blu-ray/cd-rom, narrative commercial and marketing rollouts, and other technologies that may or may not currently exist. These narrative extensions are not the same as repurposing material from one platform to be cut or repurposed to different platforms.
A transmedia producer credit is given to the person(s) responsible for a significant portion of a project’s long-term planning, development, production, and/or maintenance of narrative continuity across multiple platforms, and creation of original storylines for new platforms. Transmedia producers also create and implement interactive endeavors to unite the audience of the property with the canonical narrative and this element should be considered as valid qualification for credit as long as they are related directly to the narrative presentation of a project.
Transmedia producers may originate with a project or be brought in at any time during the long-term rollout of a project in order to analyze, create or facilitate the life of that project and may be responsible for all or only part of the content of the project. Transmedia producers may also be hired by or partner with companies or entities, which develop software and other technologies and who wish to showcase these inventions with compelling, immersive, multi-platform content.
To qualify for this credit, a transmedia producer may or may not be publicly credited as part of a larger institution or company, but a titled employee of said institution must be able to confirm that the individual was an integral part of the production team for the project.