Yes and no. This diagram lays out how to do this kind of thing cheaply and scale the systems up and down quickly. It allows the campaign to bring these systems and services "in house" instead of contracting 3rd parties to manage adding boxes at great expense at the last minute based on best guesses of expected traffic. It allows you to respond to the spikes in traffic that are expected during a campaign and during promotions that would otherwise bring your site down or have you paying for unused bandwidth.