Counter-intuitive though it may seem, the more specific your area of interest, the denser and more complex variations you're likely to find. That's true whether you're talking about quantum physics or single malt scotches.
Electronic music is no different. Although it rarely knocks any hip-hop, R&B, rock, pop or country out of the Billboard charts, wander through the fields of electronica and you'll find more subcultural subdivisions than in Balkanized Eastern Europe.
To an outsider, the stuff can be downright indecipherable.
What makes some "house music" be "minimal" and other house music "progressive"? Why doesn't "minimal techno" sound particularly minimal? If this is supposedly "trance" music, how come the beat is so mechanical? Why is some dance music considered "intelligent," and how, by the way, is "glitch" (a term that suggests your stereo system has short-circuited) a good thing?
To help clarify, here's a handy guide to a handful of cornerstone genres. But before diving in, please understand that genres are flavors, not recipes. Few, if any, artists adhere to a particular style.
What's more, no one agrees on anything. Ask three DJs to define a type of music, and you'll get four different answers. That "Balkanized" comment was no joke; people take this stuff seriously, probably too seriously, and there's no reason to get caught up in the infighting. Genre definitions aren't remotely scientific, even if most electronic music is made with computers. So never let debate get in the way of having a good time.
House
Definition: Anthemic dance tunes with now-distant roots in disco; ecstatic party music often highlighted by diva soundbite vocals. As close as electronica has come to producing its own recognizable soul music.
Key acts: Frankie Knuckles, Masters at Work, Jesse Saunders
Techno
Definition: Generally less anthemic than house — perhaps best understood as emphasizing tech over sex. But then again, as Kraftwerk sang, "We are the robots," and in the age of iPhone fetishism, technology is sexier than ever.
Key acts: Juan Atkins, Derrick May, Robert Hood
Minimal techno
Definition: Even more emotionally remote realm of techno, with emphasis on monotony as a tool to both Zen-state zone-outs and cathartic freak-outs.
Key acts: Richie Hawtin, Ricardo Villalobos, Basic Channel
Glitch
Definition: Music that celebrates failure and error, built from the very sounds that most people consider mistakes, notably skipping CDs and fritzed-out circuits.
Key acts: Alva Noto, Stephan Mathieu, Oval (pre-2009)
IDM
Definition: Stands for "intelligent dance music," which doesn't exactly make nice with all that other dance music; essentially takes the sounds of dance music production and makes something conceptual and often seemingly un-danceable from them.
Key acts: Autechre, Aphex Twin, Amon Tobin
Dubstep
Definition: Music that takes a kind of taut, broken shuffle and makes it reverberate (using techniques from bass-intensive Jamaican dub music) until it unfolds into a dark fantasy of urban mystery.
Key acts: Burial, Kode9, Shackleton
Trance
Definition: Relatively more melodic house/techno music. ("Melodic," that is, relative to dance music; we're not talking the Beatles.)
Key acts: Spicelab, Paul van Dyk, Sven Väth
Electro
Definition: If robots from the 1980s made hip-hop and aspired to be pop stars, this is what it would sound like.
Key acts: Mantronix, Drexciya, Legowelt
Additional terminology:
BPM: Means "beats per minute." The higher the number, the faster the song — though you can trick your ear into focusing on alternating beats, and thus locate a slow-motion pace at half or even a quarter of what everyone around you is feeling.
DJ: Once upon a time, the deep-voiced "disc jockey" who talked on the radio between tracks. Later, the person who favored two turntables over a microphone and entertained dancers from a club's DJ booth. Today, the "D" no longer stands for "disc" (unless you count "hard disk"), as digital DJing with MP3s is becoming the norm.
Rave: Massive party with multiple electronic acts, generally held in large warehouse or outdoor area. Unlike at any other such festival-style event, the best situation arguably isn't watching an individual act, but standing at some blissful Venn Diagram spot where multiple simultaneous performances overlap in one singular, chest-shaking sonic experience.
Turntablism: The art of using turntables as musical instruments.
Marc Weidenbaum has run the ambient-music site disquiet.com since 1996. He lives in San Francisco.