Online graduate degree programs, particularly in technical disciplines, represent a fast-growing market for higher education institutions. Yet, it is unclear how online degree programs fit within students' educational investment decisions and career goals. Based on a foundation of human capital theory, and using data from a 2017 survey of students enrolled in an online master's degree program in computer science at a highly ranked US university, this study explores how motivation for seeking an online graduate degree in computer science varies by student demographics and professional background/preparation. Results show two student markets: one for career mobility, including job advancement and/or career change, and another for skill building without consideration of mobility. Our results also show that while students come from diverse backgrounds, the primary driving factor for seeking the degree is determined by relevant professional experience. Implications for future study and online instructional design are discussed.