MailChimp is a cloud-based email marketing service that allows users to design professional email newsletters and campaigns. It offers both free and paid plans, with the free plan allowing up to 2,000 subscribers and 12,000 emails per month. MailChimp provides tools to create and send campaigns, track opens and clicks, and view detailed reports on campaign performance. It also ensures emails are complaint with privacy laws and are recognized as safe by email providers to maximize deliverability.