It’s now possible to easily show specific content in Mailchimp to certain contacts. For example you may show a certain logo, text or video to certain subscribers and another logo, text or video to other people (without having to create a separate email marketing campaign).
Dynamic content is simple to use and this video shows you how to use this new feature. Content blocks can be shown using data in your Mailchimp fields or Groups (not Tags). The footer content block however does not include dynamic content options.
Conditional merge tags have been available in Mailchimp but have been difficult to use; Dynamic content makes showing content based on a condition simple.
Dynamic Content options are available with the Mailchimp Standard and Premium plans.