The evolution of music has brought forth hundreds of music variations in so many forms to the basic music categories. This diversity in music forms have categorized in alternative music those ish style music that come as slight style alterations to most popular music forms (i.e. alternative rock or rock-ish music for rock music that does not really fit into the mainstream genres of a particular time period).
Alternative music is a category coined as a sort of catch-all for those sub-genres that are unclassified but can be traced with similarities to popular genres. These alternative music are usually those that were not released commercially and are recorded on independent labels. Some music from this category, from word of mouth, would soon find its way into the mainstream and become commercially successful.
Off-Country
Country music that does not conform to the prevailing country style is generally classified as alternative music. Musicians playing alternative country music are generally those who do not subscribe to high production values and popularity concerns. Their music are of lo-fi sound quality and often incorporated strong punk and rock and roll qualities and contained lyrics that are bleak, gothic or socially aware. The range of their music spans American folk tune to rockabilly and honky-tonk to a fusion of rock and country music. Alternative country music has developed several namesakes like Americana, neotraditional, progressive country, lo-fi country, and twang core.
Not-so-hip Hip-Hop
The alternative version of hip hop has not been very popular. Artists claiming to play alternative rap or alternative hip hop are non-conformists who wish to turn from the common drug and violence-directed mainstream rap. Alternative hip-hop fuses influences from funk, rock, jazz, soul and reggae. Some of these alternative hip-hop groups have somehow found themselves in mainstream success like Black Star, Mos Def, De La Soul, M.I.A., Kidz in the Hall, Consequence, Jurassic 5 and Brand Nubian.
Electric Rock
Alternative music is most often used to refer to alternative rock. It used to be that the word alternative was used in the 1980s to refer to punk rock-inspired bands that do not belong to major record labels and have no clear genre association. There are a lot of influences in alternative rock namely, grunge, Britpop, gothic rock and indie pop. Most of these alternative rock artists were considered cult acts and recorded their albums on independent labels. Their popularity was largely due to the exposure their alternative music got in college radios and word-of-month. The band Nirvana entry in the alternative music scene has propelled the popularity of several other bands playing alternative rock music. Metallica is another group who made it big in the mainstream music world playing alternative rock.
Perhaps an offshoot of alternative rock is alternative dance music. This kind of music combined elements of dance-pop which includes forms of electronic house or techno, and alternative rock genres. Alternative dance music can be characterized as mostly electronic, pre-programmed beats and sequenced synthesizer melodies.
As there will always be popular music, there will always be a spot for alternative music. After all, there will always be music that falls somewhere in-between, music that is somewhat like but not entirely the same as what is predominantly popular at a certain period in time.