Important note about your Facebook email address
Your Facebook email address is the same as your public username. So if your Facebook URL is facebook.com/publicusername, your email address would be firstname.lastname@example.org.
Since your Facebook username is publicly viewable — much like a custom license plate number — this means that anyone who can see your public username (for example in a search) will be able to figure out your Facebook email address. However, you always have control over who can send you messages.