Office 365 is willing to help you weed out the junk mail that makes it past the spam filtering of the organisation applied to all messages sent to CIT addresses. It's up to you to decide whether you want this feature turned on and, if so, how aggressively you want it to act. Your junk mail settings live on the server, so your preferences are applied no matter what Exchange email client (Outlook 2010, Outlook 2011 for Mac, OWA) you use to read your mail.
As delivered, Outlook will put what it considers obvious spam in the Junk Email folder, and will, initially, alert you whenever it puts a message there. You can modify this behaviour to suit your personal needs and preferences.
Setting Your Junk Mail Options
1. Go to your settings by clicking on the cog symbol next to your user profile photo on the right hand side. This will open the settings drop down menu, select Mail.
2. This will open your Mail settings menu on the left hand side. Scroll down to , select Block or Allow.
3. Select don’t move email to my Junk Email folder to turn filtering off or automatically filter junk email to turn filtering on.
Turning the filter on is the equivalent of the "Low" setting in Outlook 2010, which Microsoft describes as "Only the most obvious spam is filtered out. With this setting you will probably still see some junk mail in your Inbox, but very few legitimate messages will mistakenly be put in the Junk folder."
4. Under safe senders and recipients, checking Trust email from my contacts ensures that no messages coming from addresses in your list of contacts will ever be filtered as junk.
5. Use the blocked senders section to teach Office 365 about the senders you loathe. You can specify full addresses or domains, or some of each.
6. Click save when finished.
Fine-Tuning Your Junk Folder
While reviewing your Junk folder, if you find a message that shouldn't have been marked as junk, click the Not Junk option from the toolbar over the opened message.
Along the same lines, if you find a junk message that wound up in your Inbox or any other folder, you can simply delete it, or treat all future messages from the sender as junk by clicking Junk icon on the top tool bar.