If you’ve ever tried to log into your web mail account only to find that your password doesn’t work then chances are your account has been compromised and is under the control of another person.
If this happens to you it’s important to fix this issue quickly as not only does a compromised email account mean that someone else is potentially harvesting personal information about you but the account may also be used to send spam to your friends.
With services like Gmail, Hotmail and Yahoo mail you can usually reset your password quickly using security questions that you had set up previously. Also to protect from future email hacking, consider using 2-step authentication which involves having to enter a code sent your your mobile before any password can be changed.