This is due to the extremely high rate of free email account (Hotmail, Yahoo, etc.) that are being password hacked.
Normally this is due to a poor password choice. While easy passwords (pets names and real words) are easy to remember they are also easy to guess. Automated programs (Bots) can “brute force” their way into most accounts by running a giant database of likely used passwords (i.e. – Spot, kitty, smile, password, password1, password2, etc.) while attempting to log into the email account over and over again until it works.The best defense against account hijacking is to use strong passwords.To assist you in testing your current password strength or to create a more powerful password we have provided you with this program running from within our secure pages here:
The typical hijacked email account is usually used to send out hundreds of thousands of spam email to lists from all over the internet. Your inbox will begin to fill up with “undeliverable” notifications as what “looks to be” legitimate messages from you are returned when they cannot be delivered for some reason.
http://www.pcworld.com/article/259244/yahoo_patches_password_leak.htmlLinkedIn (confirmed this on June 6) had over 6.5 million (161 million users) passwords posted on a Russian hacker’s web site. If you belong you should change your password right now!