Why is yahoo asking for my password?

Why is that when I went to yahoo it open my account without asking for my password and ID?

• Whenever I went to yahoo, my email account is automatically open without asking for my ID and password?

• Answer:

  Because you're not logging out when you finish the time before. If it's on a public computer, or a computer that other people use, then you should be sure to hit the "sign out" button near the top of the screen to make sure nobody else uses your account. This is because your computer caches certain information (like how it keeps you logged into Yahoo) to make things easier for you. But it doesn't know exactly what you want cached, and what you don't want cached.