Since the first draft version of the Sharable Content Object Reference Model (SCORM) was developed in 1999, many organizations have tried to implement it by using many different methods. Although we've seen SCORM progress over the past four years, there is still some ambiguity on what constitutes a Sharable Content Object (SCO). We do know that a SCO is a collection of one or more assets that make up a course of learning. However, SCORM does not actually define the size of a SCO. It can be a single HTML page or a series of HTML pages. It can be as simple as a job aid, as short as five minutes in length, or as long as needed. Additionally, it can have different levels of reusability and sharability depending on individual and program needs. Based on our research partnership with the Joint ADL Co-lab and our experience of designing SCORM compliant Web-based training for various sponsors, we believe the Advanced Distributed Learning (ADL) community should consider adopting a variety of standard SCO categories. The purpose of this paper is to describe these SCO categories, and to propose that the ADL community study them further and consider adopting them for consistency across the training community. This paper will discuss the proposed SCO categories, explain why they are important, and provide examples of how they could be used in a Web-based training course on Cryogenic Engineering that was sponsored by NASA and the Florida Space Research Institute. Proposed SCO categories include: Course, Course Strategy, Section, Lesson, Learning Objects, Content Objects, Job Aids, Transitions, Test Items, and Raw Media.