For Companies and Groups it is possible in the Note / History & Actvities to filter down using the "Show For:" drop down. This way you only see the data for all contacts, the contacts assocaited with the Company / Group or just those for the Company / Group.
I would like equivalent functionality added to Opportunities. So that "Show For:" within Opportunities will let me see those items that relate specifically to contacts associated wiith the opportunity, the opportunity itself or both.
This way when using reseller / agent channels (who are likely to be associated with multiple opportunities) just the relevant informaiton for a specific opportunity can be displayed.