E-tailers refer to small and medium size enterprises or individual entrepreneurs primarily conducting businesses on online shopping platforms. Although many works on e-marketplaces have been done, theory-driven studies that explain e-tailers’ source of competitiveness are relatively scarce. The current work developed an integrative theoretical model in which online social capital, structural assurance, and online word-of-month are proposed to affect e-tailers’ business performance. The current study offers implications on: 1) what are the unique sources of competitiveness for businesses operating in pure online environment; 2) how can the resource-scare e-tailers survive in their rivalry with large offline retailers.