Daisy chaining is where to would run a strip of flexwatt, then run wires to another piece of flexwatt, and then more wires to another piece of flexwatt, and in the end would have one plug going into the thermostat to control everything. Power goes from the thermostat to the heat tape and continues on through the circuit of however many pieces of heat tape you have wired to it.

T-------F1------F2-------F3--------F4-----etc.

Its a nice method but a pain to replace a section if needed. I wire mine with a plug for each shelf of tape and hook them into power strips (surge protectors) and have the power strip plugged into the thermostat.