The location for storing unwanted e-mail as determined by a spam filter. The junk mail folder or spam folder is a place used to store unwanted incoming e- mail so that it stays out of a user's inbox. How do I know when I`ve got "Junk"?! You should receive an email once a day to let you know if messages have been added to your junk mail folder. Whether it's junk mail or phishing scams, Gmail's Spam folder is great for keeping your inbox clear of unwanted email. If you find a message that isn't junk, drag it back to the Inbox or any folder.