The market in which a communication service provider specializes is often a function of the industry served. These industries can be divided into three categories: telecommunications, entertainment and media, and Internet/Web services. Some communication service providers have branched into multiple areas. Others provide communication services across all major categories.
The term CSP came into vogue in the late 1990s. Prior to this time, communications businesses were highly specialized, with little overlap between traditional telecom, cellular, cable, and Internet companies. In the 1990s, deregulation (in the US, the Telecom Act of 1996) and technology convergence began to cause massive upheaval in the industry. As companies began to offer broader portfolios of communications services, traditional categories were inadequate to describe service providers. The term "communications service provider" is now widely accepted as a broad category encompassing all of these businesses.