Mailchimp is an email marketing platform that allows users to design and send newsletters, track results, and integrate with social networks. It offers features like templates, A/B testing, analytics integration, and spam control services. Mailchimp provides options for basic, growing, and pro-level marketers and has free and paid plans depending on the number of subscribers. It uses a double opt-in process to help users stay compliant with spam laws. Creating and sending a campaign involves three simple steps - designing a template, creating the campaign content, and sending or scheduling the message.