This chapter aims to describe how cultures have emerged in interactions among users of the multitude of online platforms that have become available over the past few decades. It discusses innovations regarding uses of representations to communicate identity, time, and space in social practices with technology, and how cybercultures are played out in theory and in practice. Cybercultures resemble cultures in the non-virtual world—but display significant differences regarding social rules, identity, and spatiotemporal issues. Case studies of three types of cybercultures in social media: information and knowledge building on Wikipedia, culture, and virtual world building on Second Life, and dating practices on online dating services, such as Tinder, will shed light on how cyberspace allows for developing both symbolic representations and social practices through computer-mediated communication (CMC), and how users are situated in the continuum virtual-real.