You'd never hire a wedding cake baker without a consultation, right? Sure, they can craft a beautiful cake, but they need specific details to make it personal for you. Your wedding colors, theme, flavor preferences and food allergies must be acknowledged — otherwise your cake won't be unique or appropriate.
The same holds true for business promotions. If you want your marketing partners to create spot-on web campaigns, they need to access your Google Analytics to gather data and thoroughly review it. Think of it as the ingredients necessary for the perfect cake.