Firstly, I would like to congratulate all those involved in creating the MagPi. The magazine reminds me of the computer magazines from my youth, and I look forward to the next one!
Now for the (hopefully not too) dumb question. One of my main uses for the Pi is to start learning some more about electronics and experimenting with interfacing, so I am enjoying the In Control articles. This month's piece talks about digital logic states, and the need for a pull-up resistor to tie the IO port to 3.3V. This makes sense to me however my question is why is the separate 10K resistor necessary - is the connection not already present through the LED and the 470 resistor?
My experiments seem to suggest it works without the separate resistor, but I am keen to understand if I am missing something?
Oh, and if anyone is looking for male:female jumper wires in Maplin, you can get some small (4.5cm) ones described as interconnect cables (A39GF).