You can turn on a setting for each individual user that will prompt you to add you comments in an Activity Journal to an open Opportunity (if you have one or more for the same customer/manufacturer combo).
“Settings” > “Application Settings” > “User Custom Features” tab > click “Activity Journals: Push Comments to Opportunity Reporting Comments” and put a check mark next to all the user’s names.
Create an AJ for the same customer/manufacturer combo. After you type the comment in the field next to the manufacturer name, click in any other field and a box will pop up showing you open opps. You can then choose to link the AJ to any open opp.
You will then see the AJ comments in the “Comments” section of the Opportunity you selected.
