If someone wishes to tell you why their line of conversation is important don't chastise them. But ask for clarification form others as well. Tracking can minimize frustration on the part of participants who feel that no one is responding to their ideas. It can also clarify for the facilitator all of the trains of thought being considered. Often one or more speakers may try to monopolize the discussion leaving everyone with the false impression that their idea is the one favored by the group.
Tracking can introduce a little more clarity.