An activity stream is a list of recent activities performed by an user, on an emakin. Activity stream is unique for each user in the system and users can't see other users activity stream list. Also activity stream is used to sent message to other users in the emakin.
Add comment in to message field.
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Cancel
Cancel is canceled action button.
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When you sent message to your collaborator, your collaborator will see your message in to her/him activity stream page.