Yes, that page is requesting a credit card number. No, Live does not have a monthly subscription fee. As the page states, they simply want to ensure you’re an adult.
As any savvy ecommerce retailer can tell you, the most challenging part of the online sale is the checkout. It’s easy to throw virtual items in a virtual shopping cart, but you have to commit when it comes time to pay. So site owners try all kinds of things to minimize the hurdle and get them through the messy part as quickly and effortlessly as possible, lest they change their mind. Meanwhile, Microsoft is taking this same large mental hurdle and trying to turn it into a speed bump. I can’t think of a faster way to send potential new users running for the hills.
Don’t get me wrong, using a credit card challenge as identification is perfectly fine when there’s a darn good reason for it; using it to ask “are you an adult” before opening a free messaging account is not one of them. Why is a kid with a Live account a problem? Are the risks greater than other such messaging services, or the Net at large? I suspect that the Live team is simply trying to avoid the legal hassles, but haven’t AIM, Google Chat, Yahoo IM, and their own MSN operated just fine for years without an age challenge? I think the answer is an obvious “no” to all of the above.
Were it me, I’d take my chances facing legal nonsense and give kids a greater level of access than adults. Children and young adults most rapidly adopt and embrace new technologies. IM, P2P, txt'ing, Facebook…all of these tools owe most of their success to users who, by and large, do not have credit card numbers. To willing cut them out of the deal is to quite literally cut your chances of success by more than half.