You must have been installed number of Apps in your facebook Account,google Account, twitter Account, yahoo Account and much more.When you install an application in any of your social networking site it takes permission to take your personal Information not all application does but be careful while you give access to any unauthorized app this may take all your personal information to his/her marketing .If you had given permission to take your personal information to the admin of app obviously he can take your Email address and will be able to send you Spam massages. 
Remove all unwanted Apps from this site be Secured and Safe…….
