The blue bits are the Power Bits and provide electricity to your creation.
Note: on each blue bit, there is the letter "p" followed by a number. This denotes the technical name of the component.
The power Bit converts the 9 volts of electricity in the battery to the 5 volts that littleBits circuits run on. The power Bit also sends a signal through your circuit. Controlling this signal with inputs is how you control your circuit. Use the small power switch on the side of the Bit to turn your circuit on and off.
The USB power Bit converts the input voltage via a micro usb cable to the 5 volts that littleBits circuits run on. Plug it in to a computer or a power cube, and power on your littleBits circuit instantly.