i have a question, for a workflow.
I want to have acutal customer list, and every one, who is in the list get every month a mail, if the contact is actual. If yes, the customer click yes, if not, then you have the possibilty to Change the contact.
Do you have any idea?
Sounds like you need a site workflow that will loop through your data and email each customer to ask
Site Workflow - Document Review Date Approaching Reminders for an idea of how they work