How do I find users who have resubscribed via {action.resubscribeUrl}?
I checked in the code [CRM_Mailing_Event_BAO_Resubscribe::resub_to_mailing()] and the resubscribe function does not unfortunately leave any traces of the action (in logs or otherwise), does not do anything if the person is already included in the groups used for mailing, and just adds the contact to the groups used for mailing for which the contact has the 'Removed' status.

So this leaves you with 2 sub-optimal solutions:


if you want to start tallying these from now on, and have PHP programming skills, you can create a simple CiviCRM extension that would implement the hook unsubscribeGroups and log all operations of type 'resubscribe' (cf. https://wiki.civicrm.org/confluence/display/CRMDOC/hook_civicrm_unsubscribeGroups)
if this is too late, or you do not have the skills, you can always search for contacts that have been recently added to the groups you are using for mailings, but this will be vastly incomplete as missing all contacts that have never been unsubscribed in the first place.