Links to a participant profile are of the form
<org_id> is the organization id of your event
<profile_id> is the talque profile id of the user
<action> is one of the actions listed in the following. Valid are
profile as the action url component opens the details page of that profile
chat as the action url component opens the chat page for that profile
meet as the action url component opens the meeting time finder that suggests convenient meeting times for both participants.