EL wire isnt like fiber optics. its an electricly charged element, just like the phosper (sp?) elements that are glowing right now in that big screen in front of you. its made up of a thin copper wire coated with the stuff, then wrapped in Very fine wire and the whole mess is coated in clear plastic tube. pass the right alternating current through the wirews at the correct frequency and it lights up brightly, in many colors that are based on the exact materials and voltages. its fairly flexible and does not produce as much heat nor consume the power needed by neon lights.
the soldering thats mentioned is connecting the embedded wires to battery powered ac adapters that run the lines.
this is jsut an offhand description from somewhere or another, IM sure someone will come along and clear this up, or at least publicly humiliate me for my ignorance. after all, thats one the the founding ideas of the eplaya