In order to use some features of Dropbox as well as post in our forums, the email address for your account needs to be verified.
If you've ever clicked on a link in an email we've sent you, you're all set—your email address has already been verified. If your email address hasn't been verified yet, we'll give you a heads-up as needed (for example, the first time you accept a shared folder invitation). You can also do it right now:
Check your spam folder to make sure it didn't end up there. You can also add the email address firstname.lastname@example.org to your address book or change the email address for your Dropbox account, then try sending the email again.
If you ever change the email address for your account, you'll need to verify it again the next time you do something like send a referral or shared folder invitation.