to answer my own question ... found some info on the web ... this is too funny!
check this:
-Started in the DC area in 1987/88 with bands inspired by that area's post-hardcore acceptance of new, diverse sounds within the punk scene. Moves onward to New Jersey and California, then onward to Philly, Richmond VA, a bit in Canada, a bit in Illinois, and not much else.
-Musically there's a lot dynamics between ultra-soft / whispered vocals / twinkly guitar bits and full-bore crashing / twin Gibson SG guitar roaring / screaming vocals. One of the most recognizable and universal elements of emo shows up in the guitar sound of this style: the octave chord. Octave chords give this style a high-pitched, driving urgency and a very rich texture. The Gibson SG / Marshall JCM-800 guitar combo and Ampeg 400 bass amp is the classic emo gear. Solid-state amps are unheard of.
-The vocal style is usually much more intense than emocore, ranging from normal singing in the quiet parts to a kind of pleading howl to gut-wrenching screams to actual sobbing and crying. Straight-edge boys tend to hate that part, and much derision is levelled at emo bands on this point. Most emo bands tend to have some epic-length songs that build up very slowly to a climax where someone cries. If you're receptive to this kind of thing, it can be extremely powerful and moving, since it's very hard to fake that kind of pure emotion convincingly.
-Lyrics tend toward somewhat abstract poetry, and are usually low in the mix and hard to decipher. Record inserts have lyrics, but often so disorganized and haphazard that they're very difficult to read [unless the record was released on Ebullition Records, in which case there are many inserts on small, brightly-colored papers containing poetic writing from the label owner and all his friends about disillusionment, anger, and things that happened when the writer was four. Such writing is known as emo writing, and there are many, many zines just like that]. Said inserts are almost always done with antique typewriters or miniscule hand-lettering, containing no punctuation or capitalization. Often the only information about the band listed is the band members' first names. Another trait of really emo records is to have no information whatsoever about song titles.
-Artwork, too, tends toward abstract black-and-white photographs of rusted/broken things (especially machinery), drawings of flowers, and pictures of old men, little boys, and little girls. Lots of live photos indicates the band is probably from the East Coast, and probably listened to straight-edge at some point.
-Live emo bands tend to play with backs to the audience during the quiet parts. During the loud exploding parts, the musicans have a tendancy to jump and shake unpredicatable and knock things over - especially mike stands. Combine this with the fact that the singers often fail to make it to the mike in time to sing, and decide just to scream at the absolute top of their lungs wherever they are when the time comes, means that often entire shows will pass without the audience being able to hear the vocals. If, however, the band has a lot of screaming during the quiet parts, this can be an extremely powerful tactic.
-The is a particular emo dance sometimes seen in the audience at emo shows. It's known as "the emo tremble." The trembler clasps his/her hands together (wringing them from time to time), leans forward, bounces quickly on the balls of the feet, and shakes the upper torso in time to the music. Once in a while the trembler will grab the back of the head and rock back and forth. The more the person likes the band, the more he or she will double over. Also, a reader submits: "i think you forgot the "emo chest tap" or just "the chest tap". this goes on a lot in the northeast...i particularly remember lots of chest tapping occuring at shotmaker shows."
-Commercialism is very much repressed in this emo scene. Few bands make t-shirts. Most records are put out on very small, home-run labels or on the band's private label. Records are sold cheap (the classic pricing scheme was $3 7"s, $5 LPs, and $8 CDs. Inflation has driven these prices up in recent years). Shows are univerally $5 or less, and touring bands often are lucky to get gas money (despite the promoter usually not paying local bands).
-There is also a bias against digital technology within most bands. Emo recordings tend to be analog only, cheaply done, with a tendency toward mostly live tracking with few overdubs. Equipment is heavily weighted toward tube gear. Until recently, most emo records were made on vinyl only. CD reissues of broken-up bands' discographies are becoming common, though.
-Lastly, emo bands tend not to last long. It was not uncommon an emo band's only recording to come out posthumously and much delayed. Obviously, this puts a damper on the distribution of the records since no one in the band puts much effort into promotion.