My "Yahoo Mobile" connection was recently hacked by 115.184.155.90 in Calcutta, India... An email was sent to everyone in my Yahoo Mail "Contacts"! The only mobile device I use is an iPhone... Was my iPhone hacked?
Highly doubtful. Chances are your yahoo account was hacked from a remote pc.
typically its just a script kiddie that gets a hold of your account by running a script at yahoo.com and if they get lucky they may end up with logins and passwords for accounts.