[zaphodp.jensen]

Simply, shift registers are just a way to pass a value from one iteration of a loop to the next iteration of the loop. They require a "host loop" that they connect within.

Loop iterations (0 is the initial value passed into the shift register)
0 1 2 3 4 5 6 7
Output (This looks weird, but due to the design of the shift register, the output comes before the input, left to right)
0 0 0 1 2 2 3 0
Input
0 1 2 2 3 0 7
Final output 7

A feedback node is basically a shift register without the loop. The shift register takes and delays the incoming signal one iteration of the vi. This would be used in Teleop, where you can't have loops.

VI iterations
0 1 2 3 4 5 6 7
Input
0 0 1 2 2 3 0
Output
0 0 0 1 2 2 3 0