Commits to notices being displayed (5,2)
I believe the answer is:
signs up
'commits' is the definition.
The definition and answer can be both to do with social activities as well as being verbs in their -s form.
Perhaps there's a link between them I don't understand?
'notices being displayed' is the wordplay.
'notices' becomes 'signs'.
'being displayed' becomes 'up' (I am not sure about this - if you are sure you should believe this answer much more).
'signs'+'up'='SIGNS UP'
'to' is the link.
Can you help me to learn more?
(Other definitions for signs up that I've seen before include "Enrols" , "volunteers" , "Recruits" .)