Tracking people in marketo. is a discussion I started a long time ago. It might be interesting for you to read the whole thing, the part that intersts you is towards the end, but if you don't understand the beginning you won't understand the end.
You would also be interested in my
Campaign Influences campaign.
Josh-
I seem to remember having system errors once for using Interesting Moments without MSI installed. Perhaps they've engineered that out since then, but as I remember you can't use I.M. without having a CRM/MSI link.