Do Triggers in the Active Secondary Database of an AlwaysOn Group Execute? If I have triggers on tables in a database that is a member of an AlwaysOn group, will they fire on the secondary? If they do fire, and they do something different on the secondary will it matter as long as it's not writing to the secondary db? For example, something external to the db, like call a service broker service, or insert into an external db if it and the table exists, will that succeed on the active secondary database?

Damien
The secondary is readonly.  Triggers can't fire on the tables in the secondary because there are no ON SELECT triggers and DML triggers cannot be executed on a readonly database without a successful DML operation (update, insert, delete).  

Updates made on the primary and then moved to the secondary do not fire triggers on the secondary.  Instead, data changes made by the triggers on the primary are propagated to the secondary in the same manner as the direct changes made to the table.