The ART area develops application protocols and architectures in the IETF. The work in the area falls into roughly three categories, with blurry distinctions between them. One category consists of protocols and architectures specifically designed to support delay-sensitive interpersonal communications via voice, video, instant messaging, presence, and other means, otherwise known as "real-time" applications and services. A second category consists of protocols and architectures to support applications that may be more tolerant of delay, including HTTP, email, and FTP. The third category consists of building blocks that are designed for use across a wide variety of applications and may be employed by both real-time and non-real-time applications, such as URI schemes, MIME types, authentication mechanisms, data formats, metrics, and codecs.