I'm wondering if anyone is using custom objects or custom activities to track transaction/purchase history? We are a financial institution and hoping other financial institutions or retail companies could share how they record buying history - or if they even pass this information to Marketo? Ideally, we'd like to have card details as well as transaction history. Is this better done through a custom object or custom activity? Lastly, does anyone know if Marketo can encrypt fields within a custom object or activity?