Normally you can't define a "standard" goal for new posts or threads because they use AJAX (not a unique URL, which is what Google Analytics goals are based on). But you can use Google Analytics events to do it (which is how the addon does it).
Lets you do things like use Analytics to cross reference by any Analytics dimension. For example, you can see source/medium correlated to how many conversation messages, posts, profile posts are being created by that source:
Same with user registrations... not just raw day to day numbers, but you can see what source are bringing you the new users (broken down also by how they signed up on your site... via Facebook account, etc.):