A microgenre is a specialized or niche genre. The term has been used since at least the 1970s to describe highly specific subgenres of music, literature, film, and art. In music, examples include the myriad sub-subgenres of heavy metal and electronic music. Some genres are sometimes retroactively created by record dealers and collectors as a way to increase the monetary value of certain records, with early examples including Northern soul, freakbeat, garage punk, and sunshine pop. By the early 2010s, most microgenres were linked and defined through various outlets on the Internet, usually as part of generating popularity and hype for a newly perceived trend. Examples of these include chillwave, witch house, seapunk, shitgaze, vaporwave, and cloud rap. Hyper-specific formulas and subgenres have always featured in popular culture. In a 1975 French article about historical fiction, "microgenre" and "macrogenre" were invoked as concepts. The author defined microgenres as "a narrowly defined group of texts connected in time and space", whereas macrogenres are "more diffuse and harder to generalize about." Further discussion of the microgenre concept appeared in various critical works of 1980s and 1990s. Historically, musical microgenres were usually labelled by writers seeking to define a new style by linking together a group of seemingly disparate artists. For example, when Lenny Kaye invoked the phrase "garage-punk" in liner notes for the 1971 compilation Nuggets, it effectively created a style of rock music that, until then, was nameless and lingering in obscurity. The process of recognition for "power pop" was similarly formulated by a circle of rock writers who advocated their own annotated history of the genre. Music journalist Simon Reynolds has suggested that early examples of "genre-as-retroactive-fiction" include "Northern soul" and "garage punk", both of which were coined in the early 1970s, and later followed by "freakbeat" and "sunshine pop".