NewsBrain uses the feedly service to fetch news articles, and until now you had to sign in with your Google account (or make a new Google account). Starting today, you have the option of using a Twitter, Facebook, or Microsoft account, as well as Google. So if you have any one of those accounts, or don't mind creating one (they are all free to create), you are good to go!
The first time you use NewsBrain, it will show a screen letting you choose or create an account. More details are here.