I know every company does it differently and that it's a complicated process, but I'm working on setting up source attribution in Marketo.
First, I would like to know....are we using the Not Visited Web Page filter correctly for our Direct Traffic smart list?:
(Since this could be a double negative, should we be using "Querystring is not empty" or "Querystring is empty"?)
Next, how do we keep people out of our Direct Traffic campaign (smart list image above) who should be falling into our Paid Search - Google campaign (smart list image below)?
(These people are clicking on our Google ads but still being attributed to direct traffic for some reason.)
Please run a search on Attribution modeling in the Community. There are many threads dedicated to this topic. Here are great posts created by Justin Norris and Erik Heldebro
Reporting and Attribution in Marketo: Comparing Your Options
First, Last and Multi Touch attribution for UTM parameters and auto tagging emails