This study attempts to improve the understanding of the rapidly growing online video platform market such as Youtube and OTT, and to investigate the attributes and relative importance of them. For this purpose, the factors that influence the choice to use were derived through literature studies and the Focus Group Interview (FGI), and the priority of the factors was calculated through the analytic hierarchy process (AHP). The upper layer of the AHP structure was ‘Relationship’, ‘Entertainment’, ‘Informativity’, and ‘Convenience’, and the lower layer was structured into 13 elements. The importance priority analysis among the factors that influence the choice to use was done by teenagers, 20s, and 30s and the results are summarized as follows : First, Users consider the ‘Just for fun’ and ‘Satisfaction of interests’ as the most important factors, followed by ‘Easy accessibility to use’, ‘Vicarious satisfaction’, ‘Usefulness of Information’, and ‘Up-to-dateness of information’. Second, the ranking of the upper layer was in the order of ‘Entertainment’-‘Informativity’-‘Convenience’-‘Relationship’.As a result of AHP,‘Entertainment’ was 3.6 times more important than ‘Relationship’. In the comparison by age group, only teenagers regarded that ‘Convenience’ is more important than ‘Informativity’. According to the characteristics of the age group, the lower layer of teenagers consider ‘Convenient function’ to be important and ranked ‘Usefulness of information’ in 8th. While ‘Vicarious satisfaction’ ranked 4th out of 13 factors in the entire age group, those in their 20s and 30s ranked 8th, showing a difference. In the case of 20s, ‘Reasonable price’ was ranked 4th and the ‘Diversity of Information’ was ranked 5th, Otherwise 30s consider ‘Trustworthiness of Information’ to the third. Third, unlike ‘Convenience’ which was the lower-rank in the upper layer AHP analysis, ‘Easy accessibility to use’, the lower-layer of convenience, ranked third overall in the importance analysis among the 13 lower-layer factors, and showed a similar patterns in the age groups results. In the conclusion, this study demonstrates that ‘Convenience’ and ‘Vicarious satisfaction’ factors, which were not relatively well addressed in the previous studies, are the key factors to be considered in. By presenting the results of the importance analysis on each of the selected attributes, This study has a practical implication that Industries such as on-line video service platform provider can use the importance priority in establishing the directions of future strategy.