Superline describes both braided and fused line.  Each get their name from the process used to create them.  Braided line is created by weaving together individual strands of line, most commonly Dyneema or Spectra fibers.  Sufix 832, one of the most popular and highest performing braided lines, uses 7 strands of Dyneema fibers and one GORE® Performance Fiber.  The Dyneema fibers provide high strength and sensitivity, hydrophobic water-repellent protection, and small diameter.  The GORE® Performance Fiber improves abrasion resistance, increased casting distance and accuracy, and reduces line vibration.  Fused line is created by fusing fibers together.  Berkley Fireline Fused Crystal uses Gel-Spun Polyethylene Microfibers that creates a line that is three times stronger than comparable monofilament lines, incredibly thin diameters, and no line memory.  Superlines provide anglers with abrasion resistance, thin diameter, minimal stretch, minimal line memory, and excellent strength.  Recent advancements have improved casting distance for superlines.  The minimal line stretch provides anglers with incredible feel that increases bite detection and good hook setting power.  Superlines excel in jerkbait situations as the minimal line set helps with hook sets.  Also superlines help with hook sets for all bony mouthed fish like walleye, bass, pike, and muskie.  Superlines are also popular with bass fishermen who fish around heavy cover and anglers using baitcasters.  There are certain fishing situations where superlines fall short.  Such as trolling or casting crankbaits, as the low line stretch can cause the bait to pull away from the fishes mouth.  This can be compensated by loosening the drag or using a rod with a fast action tip.