This study explored factors influencing platform usage from the consumer perspective. Based on social identity theory, it was premised that individuals on platforms would not prefer to deviate from the networks to which they belong and would reinforce status quo bias. Therefore, rather than the approach of prior research focusing on consumer motivations for platform use, this study sought strategies to maintain customer engagement by exploring service quality factors that affect continuous usage intention. Since individuals sometimes use platforms based on specific motivations but often use them habitually, the approach taken in this study is also necessary. First, a primary survey was conducted to establish a measurement instrument for evaluating internet platform business service quality. The primary and secondary surveys employed qualitative research methods with different respondents. The service quality of internet platform businesses showed no significant differences in constituent elements compared to existing internet service quality including online shopping, but differences were found in content. Internet platform business service quality consists of ten dimensions: fulfillment, system availability, ease of use, responsiveness speed, responsiveness, design, personalization, enjoyment, reputation, and privacy, and in terms of content, it reflects the characteristics of businesses that are more complex and diversified than existing internet services, as well as the characteristics of customers as agents of production, distribution, and consumption. Next, through the secondary survey, we confirmed whether functional differentiation of platforms is occurring according to social networks, explored whether the importance of the derived service quality dimensions differs across social networks, and explored the influence of platform services at each stage of the purchase decision-making process. As a result, closed-type SNS was mainly used for fellowship network participation purposes, with ease of use, responsiveness speed, system availability, fulfillment, and enjoyment considered as important factors. Portal-based platforms were mainly used for information-sharing network participation purposes, with ease of use, system availability, fulfillment, and reputation considered as important factors. For hybrid network participation purposes, open-type SNS was mainly used, with enjoyment considered as the most important factor, followed by privacy, ease of use, system availability, and personalization in order of importance. The influence of platform services differed at each stage of the purchase decision process. The attention stage was most influenced by fellowship networks, the interest stage by hybrid networks, and the search stage by information-sharing networks. At the sharing stage, there was a possibility that different types of information would be shared across different social networks, and the action stage was found to be largely unaffected. Based on these results, this study presents hypothetical propositions along with strategic implications for platform business research and platform and business ecosystems.