The best emails feel personal. And they are. Flash sales site Gilt Groupe, for example, sends over 3,000 variations of its daily email, each tailored to past user click-throughs, browsing history, and purchase history. Of course, building true customization and targeting abilities is a transformative process that requires specific capabilities and supporting infrastructure. Customer information – which often lives in different parts of the organization – must be aggregated to create a single view of each consumer. A targeting engine must be built to guide the right message to the right person. And operations need to be ready for the change; creating and sending 3,000 emails per day is very different than sending one mass email blast.