Another built-in comment field is the "Important" flag. When an important conversation was made, it can be flagged as important. These conversations can be easily listed using the Conversations / Important conversations submenu. The important conversation list is maintained separately for each user (every user has different important conversation list).
Important conversation flagging is built into the commenting feature. The "Important" flag is a built-in comment field of the default comment template.
To remove the important conversation flag, just uncheck the checkbox on the conversation detail page and save the record.
Conversations can be flagged as important directly from the telephone with the Verba XML service. For further information see Flagging a conversation as Important.