Post-Grunge refers to the wave of bands who appeared shortly after Seattle grunge hit the mainstream. The major difference is that while the Seattle bands were firmly rooted in underground alternative rock of the '80s, post-grunge was influenced by what grunge became -- a wildly popular form of inward-looking, serious-minded hard rock. That meant many post-grunge groups imitated the sound and style of grunge, but not necessarily the individual idiosyncracies of its original artists. The angst-ridden, sober introspection typically associated with grunge became virtual requirements in the hands of post-grunge, which tended to view it as a path to artistic legitimacy. In its worst excesses, post-grunge took itself extremely seriously, and was highly self-conscious about its own significance; as a result, grunge's most personal aspects essentially became components of a formula for making grand musical statements. That wasn't universally true, of course, but post-grunge did help codify what was expected of mature, mainstream hard rockers for the rest of the '90s. And despite its alternative roots, post-grunge was definitely a mainstream, commercial style -- it was released on major labels, and its thick, distorted grunge guitars were given a polished, radio-ready production. Yet while much post-grunge is similar, it isn't identical; in addition to grunge, post-grunge bands might draw from early-'80s jangle pop, punk-pop, ska revival, alternative metal, or classic album rock. Plus, a few quirky post-grunge outfits succeeded because of their wiseass senses of humor, rather than the style's typically dour melancholy. After grunge's breakthrough, it didn't take long for post-grunge to appear; bands like Bush and Candlebox became huge successes just a couple years after Nirvana topped the charts at the beginning of 1992. After grunge's initial heyday had passed, post-grunge kept going strong, with a new wave of bands appearing in the mid- to late '90s; some were able to maintain their popularity from one album to the next, while others wound up as one-hit wonders. At the turn of the millennium, post-grunge was still a popular style, and Creed and Matchbox 20 were two of the biggest-selling rock bands in the U.S.