Now you need not fill in all your details to create a Yahoo account, If you already have a email id of any provider you can create a Yahoo Account with that email.
Here is what the Yahoo Blog post says:
Meet Jack. Jack wants to play Yahoo Fantasy Sports so he can have some Tourney Pick’em fun. Like most people, Jack already has an email address. It isn’t a Yahoo email address, though.
Yesterday, Jack would have had to create a new Yahoo email address just to sign up for Yahoo Sports Tourney Pick’em. That’s not fair to Jack and just doesn’t make sense. He will probably forget the Yahoo email address he created just to play and won’t check his inbox very often, so there’s a good chance Jack will miss important emails about the status of his picks, his pools, etc.
Well, today is Jack’s lucky day because we’re excited to announce that Jack (and everyone else) can sign up for a new Yahoo account without having to create a new Yahoo email address.
Jack can use his existing Gmail, Outlook or any other non-Yahoo email address to create a new Yahoo account and start playing Yahoo Fantasy Sports right away. Even better, he can use this new Yahoo account on other Yahoo products like Finance, News, Messenger, and more!
We want to make it as delightful as possible for users to sign up, sign in, and stay signed in because this lets us deliver the best possible experience. Starting with Yahoo Fantasy Sports, like Tourney Pick’em, we’ve upped the ante with this new registration experience and will roll this into other Yahoo products soon.