User tag email v1.4 changes:
Added canonical code to email links.
User tag email v1.3 changes:
Updated options page descriptions to make it more clear what each field does.
User tag email v1.2 changes:
Added code to follow "Receive site mailings" preferences.
User tag email v1.1 changes:
The options page now allows selecting 'all', this allows all members to receive an user tag email notification.