The three inputs at the bottom control the address. The top & leftmost input stores the data to the memory. The input below that loads the data to the output (LED). The input closest to the LED is the data that will be stored in the memory. The topmost input wipes the memory.
How it works: The address input is connected to a multiplexer (right) and a demultiplexer (left). The data coming in is directed to an SR flip-flop by the demultiplexer. The multiplexer chooses which SR flip-flop to get the data from. AND gates act as switches so data does not always have to come in and out.
[Multiplexer: http://everycircuit.com/circuit/4707980243632128]
[Demultiplexer: http://everycircuit.com/circuit/4684685750304768]
(version 1 is http://everycircuit.com/circuit/5675886343356416)
Version 2 has less address selectors. This is more efficient because it minimizes the pins, and it will take less time to switch between addresses.
