This month an individual from Europe known only as Hacker Croll
was able to log into a Twitter employee's personal Gmail
account.  He gained access after he found a password the
employee had used for a different web site; the password for
that web site and the Gmail account were the same.  Once in, he
was able to see the employee's emails and confidential file
attachments.  The problem is that most of us are guilty of the
same password no-nos:    1. We use the same password over and
over again, for different sites and applications   2. We choose
simplistic, "easy to remember" passwords that might be easy for
a hacker to guess (the most notorious are "password" and
"secret")   3. We keep the same password for years, without
changing it  Our system has solid security, but our security
won't do you any good if someone is able to guess your
password.  To ensure that your account is kept safe, you should
change your password regularly.