This history behind this goes back a few months I think. I can't recall that exact details, but someone somewhere managed to get a hold of a number of Apple ID account details, through some rather nasty code that managed to get through the Apple App Store censors. Apple decided to implement some further security measures, akin to those for online banking, whereby in addition to account ID and password (like Account number and PIN), you provide some answers to a series of questions that only you are likely to know all the answers to. So in the event your Apple account is compromised, it will be easier for you as the real account holder to get control back. Bearing in mind that the Apple ID account usually has access to your credit card details, and therefore carries a similar financial risk to handing someone your bank card and PIN details.