The natural environment of a microbe is typically crowded and diverse. Although we have sophistication in the understanding and even design of populations containing a single type of cell, the ability to predict and control multispecies communities of microbes is still in its infancy. New approaches are needed to understand how interactions within diverse microbial communities influence the function of both individual cells and cellular networks. One hurdle towards a predictive understanding of community dynamics is accounting for the multiple types of interactions that occur within diverse communities. Although many approaches focus on metabolic interactions between species, the exchange of signaling molecules, ions, and even genetic material play an important role in governing community behavior. Understanding all the mechanisms through which microbes interact, especially interspecies interactions, will be a key step towards both controlling natural communities and designing synthetic microbial communities.