What is a Salt Cell?

The cell (or Electrolytic Cell) is the plumbing component of a saltwater pool system. It is basically a PVC tube that holds a stack of titanium plates inside. Briefly, what happens is that as salt water passes through the cell, the salt system sends a weak electric charge through the water between the titanium plates, which converts salt into chlorine. In essence, your salt system is a chlorine generator which (in terms of operation) you can treat in a similar way as you would a chlorine tablet dispenser. However, you have to fill up a chlorine tablet dispenser as it gets used, don't you? So then what gets used up on a chlorine generator?