As of January, 2016, the designation of incoming email as spam is handled differently, so you may see some changes in your email spam designation.
Marking an email as NOT spam:
If a legitimate email message gets accidentally marked as spam, you can remove it from the spam folder by opening the message and clicking the "Not spam" button in the top menu bar. This will move the email message to your inbox where it will be safe.
Messages tagged like this...
...are routed to your spam folder using the University’s rules rather than Gmail's automated spam detection system. In this case, please send a screenshot of the message, along with the message content and mail headers to firstname.lastname@example.org. After that you will also want to click the “Not spam” button in the top menu bar as described above.
Marking an email as spam:
If you get an email in your inbox that is actually spam, you need to click the "Report Spam" button (looks like an exclamation mark inside a stop sign) in the top toolbar to move that message into your spam folder and to help teach Gmail to treat such messages as spam in the future.
For additional information see spam and suspicious emails