For all the account we set on the internet, such as website accounts, forum accounts, emails, social networks, and etc., we can find back/reset password through "forgot password" option.
For the offline accounts such as bank account transaction passwords, shopping mall club member password and etc., we might should contact the bank and the shopping mall service window physically. By confirming our identity, we can get the password back.
In case we forget the password somehow, there are many good password manager applications for us today. Try to find the one match your needs of saving and managing passwords, that you will never forget them anyway.
For example, with Yahoo! Mail, visit 'Forget your ID or password?' found below 'Sign In' in the Login page. It requests 'Yahoo! ID'. Enter requested details. These include birth date, ZIP code, location as well as security image. Then enter your specific Yahoo! ID to obtain a new password.
Similarly in Orkut, the widespread networking site, see 'I cannot access my account', and then opt for 'I forgot my password'. It asks for email address always used so as to sign in to your particular account. For Gmail users, the Gmail username needs to be entered.