Ask HN: Infusionsoft Campaign Builder – how does it actually work?

Sure, you're not going to know exactly, but can you hazard a guess? I've used the frontend (examples: http://ug.infusionsoft.com/article/AA-01060/0/Campaign-Builder-Overview.html) and it does my nut in that I can't figure out how this data is stored in their database (assumption #1), how if an event is triggered someone is moved from point C in a campaign to point D, and how someone can be in multiple campaigns at once. The hacker in me has tried to figure this out and failed. Give me your speculation, your knowledge... just help me with how does it frickin work???