You may adjust spam filtering overall sensitivity and spam category sensitivity for an individual user by completing the following steps:

Individual Users:

1. Login to the Postini portal as a System Administrator
2. Click the Orgs and Users tab
3. Click "List Users" next to the sub-org containing your users
4. Click on the user whose filtering settings you wish to adjust
5. Select "Spam Filtering" under Inbound Services
6. Adjust the Bulk Email and spam category settings as desired