When designing social robots, it is crucial to understand the diverse expectations of different kinds of innovation adopters. Different factors influence early adopters of innovations and mass market representatives’ perceptions of the usefulness of social robots. The first aim of the study was to test how applicable the technology acceptance model 3 (TAM3) is in the context of social robots. Participants’ acceptance of social robotics in a workplace environment in the fuzzy front-end (FFE) innovation phase of a robot development project was examined. Based on the findings for the model, we developed a reduced version of the TAM3 that is more applicable for social robots. The second objective was to analyze how early adopters’ and mass market representatives’ acceptance of social robots differs. Quantitative research methods were used. For early adopters, result demonstrability has a significant influence on perceived usefulness of social robots, while for mass market representatives, perceived enjoyment has a more significant influence on perceived usefulness. The findings indicate that users’ innovation adoption style influences the factors that users consider important in the usefulness of social robots. Robot developers should take these into account during the FFE innovation phase.