Noooo... how long must this go on?
Really, El Reg.
In a conventional computer, the presence or absence of an electron indicates a one or a zero. Quantum computers store information in the spin of an electron which, thanks to the weirdness of the world at quantum scale, can be in several states at once. A single electron in a quantum computer can therefore be a zero and a one at the same time, which creates the potential for parallel processing inside a chip and therefore for faster computation.
In a classical computer, bit states can be encoded by the presence or absence of electric charge. In quantum computers, qubit states can be encoded by the spin state of single electrons which, quantum mechanics tells us, can be in a superposition of states 0 and 1 akin to the superposition of an à priori unknown classical bit in classical probability, albeit here one must use complex numbers to express the "quantum probability". Interesting for computation are arrays of N entangled qubits, which express a complex probability distribution in a 2^N large space, but then one still has to manipulate this qubit vector using quantum gates to yield the computation of interest, a feat that is still a bit in the future.