Sometimes it is necessary or preferable to reference or embed third-party content that is outside of the control of the publisher but integral to the understanding of the work. For these features, anticipate that their availability may be temporary and make plans to ensure that they are not only preserved, but sustained in some form as part of the publication while they are on the publisher platform. In the case of an embedded YouTube video, for example, some options to support preservation might include: retaining or requesting a copy of the video file; getting permission to copy the content directly from YouTube using a downloader tool in order to bring it into the local publication; or web archiving the video page and linking to the archived copy, e.g. on the Internet Archive. An informative caption can help support future readers if the content is unavailable.

These guidelines may also improve preservability of third party hosted media:
12. Start discussions about multimedia early in the project
14. Avoid externally hosted media
16. Captions for non-text features add meaningful context
20. Ensure all core intellectual components of a work are reflected in the export package
39. Avoid the use of iframes to embed multimedia
42. Facilitate a local web archive workflow for iframe content