Email Marketing's Salesforce Addon allows you to sync your Salesforce contacts with a subscriber list, making it easy to keep in touch with customers and prospects alike. Even if you don't already have a Salesforce account, you can always grab a free trial, to test it out.
Don't worry! If you see that Mad Mimi is requesting permission, it's not a mistake. The engine that runs our Email Marketing platform used to be called Mad Mimi, and so the authorization screen might not have been updated. However, you can rest assured that this is for your Email Marketing account access to Salesforce, and not anything else.