When is it worth it to use Triggers and stored procedures/functions?
Triggers are problematic because they tend to get forgotten about.  I only ever use triggers for auditing purposes such as updating a "last updated datetime" column.  Stored procedures and functions can be used at any time since they are called directly by processes wishing to modify data -- as opposed to triggers that are fired as the result of data being changed.

If you are building queues to do some of the work, I suggest you also use queues to create your posts as well.