rules to mark mail as junk

05. January 2013 · Write a comment · Categories: Hotmail, Outlook.com · Tags: , ,
Mails from a particular sender is going to junk.
When I am checking the message source it  is showing SPF as pass , DKIM as pass.
But still it is being sent to junk folder . why it is marked as junk?? What are the rules that is being followed to determine if a mail is junk or not?

Thanks & Regards
Sudip