Virtual Worlds are receiving increased global attention in a wide range of applications in education, business, government and social contexts. Kock (2008) defines virtual worlds as "technology-created virtual environments that incorporate representations of real world elements such as human beings, landscapes and other objects." A key element is interaction via avatars. For example, SecondLife (www.SecondLife.com) is a virtual environment (within which real-life experiences can be attained) that has a wide range of artificial domains with user avatars encompassing aspects of visualization and sense of presence, as well as text and audio interaction. Other virtual worlds are emerging that have similar features and aspirations. HiPiHi (http://www.hipihi.com) is one such Chinese environment that has striking similarities with (as well as differences to) SecondLife. In this paper, we compare SecondLife to other virtual worlds (with special attention to HiPiHi) using an extended Technology Acceptance Model (TAM) lens. Results indicate that virtual worlds (at least in their current form) need considerable attention to numerous issues before mainstream impact is achieved. In this sense, it is a goal desired but yet to be attained. Barriers to adoption and diffusion are identified and directions for future research beyond TAM are provided. Conclusions are drawn.