I feel like I should know this but I am stumbling a little. It is my hope that the community can help.
Situation: Lets say that we have 3M people in our database and based on our contract we are permitted 5M. We are cost focused so we don't want to just dump all of our contacts in Marketo. Having said that, lets say that we have 10M people that have user ids set up with our online account portal. We don't want all 10M automatically added to our database and they may not even be in our CRM b/c they might just be people that run reports, pay bills, etc. However, of the 10M people that have accounts and do certain things (click on promo pod, abandon cart, etc) we would like to then have those people ONLY based on the business rules that we define sync to Marketo and have them introduced to our database if they aren't already. We do not want the person to fill out a form b/c the expectation is that we already know them b/c they are logged in. The idea is to introduce quality/engaged people that are known to our business but maybe not Marketo yet.
Has anyone overcome this? Do you use an API?
Any suggestions would be welcome.
I can't speak to thje SFDC integration that thoroughly but in the Sugar integration we have a boolean field on all Leads and Contacts called "Sync to Marketo" this field must be checked for a record to sync from our CRM to Marketo. We then have a rule that appends that box when a user modifies the record. I'm assuming there is some field similar in the SFDC integration which would give you flexibility to control the scenario you are referring to in many different ways.
I know this wasn't exactly an answer, but may get the wheels turning so others can assist here.