This is all down to the BBC jumping on the bandwagon of getting as much personal information from us to sell on to third parties so expect extra Spam if you give them your e-mail address.
I needed to sign up because I can't watch anything here n England without doing so and it even applies to radio now. The odd thing is it didn't apply to me in Germany a week or so back, using a netbook that hadn't been connected to Auntie Beeb when at home.
They've also started advertising box sets so you might like to keep an eye on the ones you missed. You didn't hear this from me 😀 but you might like to consult YouTube from time to time.