You can request associations with your BSC Participant IDs through your profile page, which gives you access to some dynamic site content relating to those IDs.
If you have Participant ID associations, you can visit the Participants/Colleagues tab in your profile to see other portal users who share Participant ID associations with you. You can also revoke the associations of other users who share your associations (a self management mechanism that allows you to quickly revoke privileges from users who have left your company).