I see that the usage of MBOX.js is quite similar to Google Analytics with some minor differences.
If I include mbox.js in my site header, will changes made on the admin interface of Adobe Target reflect automatically on the site, or will I have to re-download the mbox.js file.
Have a look at the basic concept regarding a Mbox here. Hope it should clear your doubts regarding how an Mbox works. Do let us know in case of any further queries.