Online game livestreaming is an emerging industry. Followers' donation is major source of live streamers' income. The reactions induced by the immediacy and interactivity of online game livestreaming are critical to viewers' engrossment in such livestreams. This study explores viewers' intention of following and donation toward streamers of online game livestreams, by considering characteristics of the livestreaming context, streamers, as well as viewers' feelings and perceptions. Results from analyzing data collected by online survey show that the relationship among loyalty, intention to follow, and intention to donate is significant. Value co-creation and flow experience are the main factors promoting viewers' loyalty. Enjoyment indirectly affects loyalty through the flow experience. The influence of user engagement, media richness, social interaction, and expertise on value co-creation and flow experience is as our expectation. But social interaction and expertise are not as important to viewers. Academic and practical implications are discussed further.