This chapter discusses the new realities of global computer online social network ecosystems, including moral and ethical dilemmas. Because we believe that a sound and detailed discussion of online social networks is based on a good understanding of the underlying network infrastructure, we start the chapter with a brief discussion of the computer network infrastructure. Based on this communication infrastructure, we define a social network and its subset, the online social network. We discuss the types of social networks, their historical development, and the different and changing services of online social networks. After discussing the basics of online social networks, we then focus on ethical, social, and privacy issues in the online social network noting that while online, we inevitably give off our information to whomever asks for it in order to get services. We note further that routinely information collected from online community members, however, is not always used as intended. It is quite often used for unauthorized purposes, hence an invasion of privacy. We discuss known ways we give off vital personal information while online in social networks. We further discuss ways to protect personal privacy. On the central point of ethical implications of life in the social network, we note that unlike in the traditional network, governance is not centralized, but community based with equally shared authority and responsibility by all users. But the mechanisms are not yet defined, and where they are being defined, it is still too early to say whether they are effective. The complexity, unpredictability, and lack of central authority are further enhanced by a the concepts of telepresence and immersion, virtual personality, anonymity, and multiple personality. These issues are at the core of the social and ethical problems in online social networks in particular and cyberspace in general; the larger and more numerous these communities become, the more urgent the ethical concerns become.