Hi ​@nburke 
The author is the only one who can update a logged activity.
Can you add a little more context? What’s your use case where a comment on the same activity doesn’t cut it?

Unfortunately, the "NOTES" section of a Timeline Activity in Google Workspace is generally designed for a single user's input, and there isn't a direct, built-in collaboration or share feature to allow multiple people to edit those notes simultaneously.

Here's a breakdown of the situation and some potential workarounds:

• Comments vs. Notes:

  • As you've noted, comments are indeed the collaborative feature within Timeline Activities. Multiple users can add comments, creating a running dialogue.
  • The "NOTES" section, on the other hand, is typically for more structured or personal notes by the activity's primary owner or manager.

• Workarounds:

  • Utilize Comments Extensively: Encourage your team to use comments as the primary collaboration tool. This can be effective for discussions and shared insights related to the activity.
  • Shared Document Integration:
    • Create a shared Google Doc that contains the collaborative notes for the Timeline Activity.
    • Link this document within the activity's description or comments.
    • This provides a central, editable space for everyone involved.

​@romihache sometimes two CSM’s are working together on a Company’s tasks simultaneously and are compiling their notes together.  It would just be nice to see them all in one space and not split up between the Notes and the Comments.

Got it ​@nburke. 
Carol’s ideas are great workarounds! I can add one more that we find useful at the customer level so they don't have to fish important data from the timeline: a rich text widget in C360 (e.g., like Summary, which is an STD field).