Do You Know That You Can Login To Your Facebook Account Using Three Different Passwords? Unlike Any Other Social Network Which Has Only One Password To Access, Facebook Lets You Login Using Three Different Variants Of Your Password. Facebook Accepts The Following Forms Of Your Password.
1. Your Original Password: This Is The Password You Created During The Sign-up Process. Assume That Your Default Facebook Password That You Created During The Sign-up Process Is "myFacebookPass"
2. Password With The Case Toggled: In The Above Password, The Letters "F" and "P" Are In Uppercase And The Remaining Are In The Lowercase. If You TOGGLE The Case Here, All The UPPERCASE Characters Are Converted Into The LOWERCASE And Vice Versa. Your Default Password "myFacebookPass" Would Become "myfacebookpass". Now If You Login Using The Above Toggled Password, Facebook Will Accept It. This Is The First Variation Of Your Default Password Which Is Accepted By Facebook.
3. Password With The First Letter Capitalized: If The First Character Of Your Password Is In The LOWERCASE, You May Just Change That First Letter To UPPERCASE And Facebook Will Again Accept It And Let You In. As In The Case Of The Above Example Where Your Default Password Is "myFacebookPass", If You Just Change The First Letter To UPPERCASE, Your Password Would Be "MyFacebookPass".
Note: The 3rd Option Works For Mobile Users Only.

Why 3 Passwords?? Now, You All Know That Facebook Can Be Accessed Using Three Different Passwords. It's Just An Option Provided By Facebook Itself To Make The Sign-in Process Easier For Users. The Most Common Reason For The Authentic Logins To Be Rejected Is When The CAPS LOCK Is ON. This Is Where The First Variation Comes In Handy. That Means, When The CAPS LOCK Is ON, The Case Gets Reversed (Toggled) For Your Password But Facebook Will Accept It. In Case Of Mobile Phone Users, It Is Common For The First Letter Of The Password To Get Capitalized Which Often Leads To Login Failure. So In Order To Tackle This Issue, Facebook Will Also Accept The Password Where Only The First Letter Is Capitalized. Thus If The CAPS LOCK Is Accidentally Enabled, The Toggled Password Feature Would Still Let You Log In To Your Account.