Or they're just asking for it.
My customers fall for this one constantly:
Dear E-mail Account User,
Important Notice We have temporarily limited access to sensitive account
features, To restore your account access, please you must reply to this
email immediately and enter your E-mail account Username here :(.................)and password here:(................)
Due to the junk/spam emails you receive daily, we are currently upgrading
all email accounts spam filter to limit all unsolicited emails for
security reasons and to upgrade our new features and enhancements with
your new and improved E-mail account, to ensure you do not experience
service interruption.
Please you must reply to this email immediately and enter both your user
name and password in the space provided to enable us upgrades your
Account.
A confirmation link will be send to you for the Re-Activation of your
e-mail Account, as soon as we received your response and you are to Click
on the "Confirm E-mail" link on your mail Account box and then enter this
confirmation number: 1265-6778-8250-83.