Hydroponic System Types

I'll update this as I learn more.

Aerogardens are a combination Aeroponic and DWC system (see below), although from all my reading, it's a stretch to call them aeroponic.

• Aeroponic: This generally means that the roots of the plants are exposed to a mist of air, water and nutrients.  I never realized this, but the roots need Oxygen!  One non-Aerogarden Aeroponic system is the General Hydroponics Vortex Sprayer.  It attempts to fill the space between the grow deck and the surface of the water reservoir with a mist of water and nutrients.  It does it very effectively
• Drip: As I've seen them, there's a mechanism to draw nutrients and water from the reservoir and drip it on the grow medium.  Aerogardens actually seem more like a drip system than an Aeroponic system, although most of the commercial drip systems I've seen have some sort of feed tube above the grow medium.  They also tend to operate as DWC systems underneath: when the plant's roots get long enough, they tend to grow down into the reservoir itself
  
• DWC, or "Deep Water Culture": A rather simple system where the plants roots hang directly into a water/nutrient solution.  Cheap and easy, and about as complicated as it gets is that you'll probably want an air stone (as with an aquarium) to pump air through the water to re-oxygenate it
• Ebb and Flow: Basically, the roots of the plants are flooded periodically, but allowed to drain.  This means that the grow medium needs to be able to hold onto moisture during the non-flood phase
• NFT, or Nutrient Film Technique: As I understand it, the roots are exposed to a thin film of constantly replenished nutrient and water mix