As a style of music, it is generally characterised by 'dirty' guitar, strong riffs, and heavy drumming. Grunge is also popularly referred to as the Seattle Sound. Independent labels were key catalysts in bringing this style of music to the public initially. Many of the more successful bands of the era were associated with Seattle's Sub Pop record label, though several other independent Seattle labels gained recognition, including Kill Rock Stars and K Records.
Besides its punk roots, the grunge movement had strong roots in the Northwest musical culture and the local youth culture. The sonic resemblance to such 1960s Northwest bands as the Wailers and, most particularly, the Sonics is unmistakable, and grunge clothing was a blend of a punk aesthetic with the typical outdoorsy clothing (e.g. flannel shirts) of the region.
The emergence of "grunge" as a genre and its embrace by the mainstream is usually thought of as a reaction against the popular dominance of hair metal. Hair metal bands, such as W.A.S.P, Poison and Guns 'n Roses had been dominating the charts, especially in the US, for several years in spite of declining critical viability. Grunge music can be sharply constrasted to hair metal's macho lyrics, anthemic riffs, and a perceived lack of social consciousness, especially in the race to attract mainstream audiences.
Grunge was embraced by the youth for its simple defiance of the then-cultural norm, which was seen by many as a corporate-dominated and superficial popular culture. In the rock world, expensive, designer clothing was shunned in favor of flannel, jeans, and Doc Marten or Converse boots. Traditional rock and roll ostentatiousness became offensive, at least for the time being.
The mainstays of this rock genre were primarily Seattle-based bands, such as Nirvana, Pearl Jam, Alice in Chains, Soundgarden and Stone Temple Pilots (from San Diego). Nirvana is generally credited for breaking the genre into the popular consciousness in 1991 (see 1991 in music). The success of Nirvana's "Smells Like Teen Spirit" (off Nevermind) surprised the entire music industry. The album was a #1 hit around much of the world, and paved the way for more bands, including, most popularly, Pearl Jam. For many audiences then and later, grunge came to be almost totally associated with these two bands and their punky, rebellious attitude towards mainstream mores as well as cultural and social institutions.
The popularity of grunge music was short-lived, however. When Kurt Cobain (of Nirvana) committed suicide in April of 1994, grunge music effectively began its decline. Ironically, Cobain had often been photographed wearing t-shirts stating that "Grunge is Dead".
The general consensus of fans and music historians is that the genre was entirely too opposed to mainstream stardom to actually achieve long-lasting popularity. Many grunge bands refused to cooperate with the record labels in making radio-friendly hooks, and the labels found new bands that were willing to do so, albeit with a watered-down sound that did not sit well with the genre's long-time fans.
For many fans of the genre, it wasn't until the dissolution of grunge pioneer band Soundgarden in 1997 that they finally conceded grunge (as mainstream music) was dead. Many grunge bands have continued recording and touring with more limited success, including, most significantly, Pearl Jam.