Segmentation is not a requirement but a wise strategy when you have a business with a constantly growing email list of subscribers or contacts. You wouldn't want to send the same email campaigns and newsletters to everyone in your email list as each of them subscribed to you for different reasons and would have different preferences of what they want to receive in their inbox. Segmentation simply involves grouping your email subscribers based on their commonalities so you can send them email campaigns and newsletters that are relevant to their characteristics or preferences. In this tutorial, I laid out the steps to implement segmentation using MailChimp.