If you have a LinkedIn or eHarmony account, you need to change your password.
LinkedIn has been hacked. 6.5 million password hashes have been stolen and hackers are feverishly working to crack those password hashes. It is estimated that over 60% of stolen passwords have already been cracked. 1.5 million decrypted password from eHarmony have also been published.
Go change your LinkedIn and/or eHarmony password now. But more than that, if you used that same password anywhere else, change it there too.
You might want to consider using a password management tool. W do not recommend password managers that are built into browsers, but ones that are stand-alone like KeePass, passwordsafe, or 1Password and that keep your passwords in an encrypted vault are very useful. Such a tool will allow you to have a different password (a strong one) for every site, but not have to remember them; you only need to remember the password to your password vault and it will insert the password when needed.