Maintaining campaigns, marketing lists and sending emails to different marketing lists in bulk are usual processes in Marketing. Dynamics CRM provides a useful set of functionalities under Marketing.
MailChimp provides lot of web based features including Email designer, Email Template Creator, integration with different web applications, maintaining campaigns, create campaigns using mobile etc…
http://mailchimp.com/
PowerMailChimp connects Dynamics CRM and the MailChimp, simply it acts as MailChimp CRM Integration tool.
http://www.powerobjects.com/powerpacks/powermailchimp/
You can create marketing campaigns, maintain static or dynamic marketing lists to send offerings, newsletters, notices etc… from Dynamics CRM itself. Also MailChimp can be used to design your email templates or newsletter templates very easily and send those emails or newsletters using your own templates in MailChimp. Statistics such as successful deliveries, opens, bounces and unsubscribes can be seen from the CRM itself.
Its simple, watch following video in YouTube;
C R M F o r t r e s s | Indika's Dynamics 365 CE Blog 