Groups are an easy way to organize your list into categories so that you only need to maintain a single list in your account. Let’s say you have an e-commerce store and use your Mailchimp account to communicate with sales representatives, retail locations that sell some of your products, and customers. The logical step might seem to be creating separate lists to track these three audiences, but adding them to groups on one list is a similar concept that can save you money. You can then build segments for these groups and send campaigns that are relevant to them.


People who subscribe to your list are so interested in what you have to say that they’re willing to invite you into their inbox. This is a privilege. Honor it by letting them be the first to know about new products and sales. Or, go one step further like the company Oui Shave that asks its best customers to participate in product surveys and rewards them by making them beta testers for new products.
A mailing list is simply a list of e-mail addresses of people that are interested in the same subject, are members of the same work group, or who are taking class together. When a member of the list sends a note to the group's special address, the e-mail is broadcast to all of the members of the list. The key advantage of a mailing list over a things such as web-based discussion is that as new message becomes available they are immediately delivered to the participants' mailboxes. A mailing list sometime can also include information such as phone number, postal address, fax number and more.

Listwashing is the process through which individual entries in mailing lists are removed. These mailing lists typically contain email addresses or phone numbers of those that have not voluntarily subscribed. An entry is removed from the list after a complaint is received. Only complainers are removed via this process. It is widely believed that only a small fraction[citation needed] of those inconvenienced with unsolicited email end up sending a proper complaint. Because most of those that have not voluntarily subscribed stay on the list, and only the complainers stop complaining because they are removed, this helps spammers to maintain a "complaint-free" list of spammable email addresses. Internet service providers who forward complaints to the spamming party are often seen as assisting the spammer in list washing, or, in short, helping spammers. Most legitimate list holders provide their customers with listwashing and data deduplication service regularly for free or a small fee.
