I believe a Google account is quite different from a Gmail account. You can turn a non-Gmail account into a Google account, by signing it up to one of their services, if I am not wrong. By using these services, your account henceforth becomes a Google account and subject to their terms, and conditions. 
<div><br></div><div>A Google account can choose to use Googl&#39;s mail servers or retain a different server. </div>