Passwords provide the first line of defense against unauthorized access to your computer or any online account. The stronger your password, the more protected your computer and your accounts all over the internet from hackers and malicious software. You should make sure you have strong passwords for all accounts that you have.
As per the 2012 research cbsnews higlights the 25 most common passwords of 2012:
1. password (Unchanged)
2. 123456 (Unchanged)
3. 12345678 (Unchanged)
4. abc123 (Up 1)
5. qwerty (Down 1)
6. monkey (Unchanged)
7. letmein (Up 1)
8. dragon (Up 2)
9. 111111 (Up 3)
10. baseball (Up 1)
11. iloveyou (Up 2)
12. trustno1 (Down 3)
13. 1234567 (Down 6)
14. sunshine (Up 1)
15. master (Down 1)
16. 123123 (Up 4)
17. welcome (New)
18. shadow (Up 1)
19. ashley (Down 3)
20. football (Up 5)
21. jesus (New)
22. michael (Up 2)
23. ninja (New)
24. mustang (New)
25. password1 (New)
For this reason most of them are get hacked easily so we found a great tool which is giving the password stength advisor from Kaspersky
http://blog.kaspersky.com/password-check/
Also see the video in bottom it will help you how to choose Strong Passwords