Most email marketing software has features that assist the user in the process of organizing contacts, creating campaigns, and scheduling communication. In addition, the software usually provides features, such as an "unsubscribe check" that assist in complying with the CAN-SPAM law. Email Marketing software can also provide tracking functions such as how many people have opened an email, how many emails bounced-back, how many people visited the hyperlinks provided in the marketing message, and how many people actually purchased something as a result of the email. Each email service provider has their own take and approach to these different features some of the most common are listed below

The common features are listed below:
* Ability to create and send personalized email using data from a customer database.
* Ability to import customer lists
* Split campaign testing and segmented lists
* Surveys
* Automatic unsubscribe and bounce-back handling
* Ability to authenticate to SMTP and POP servers or send directly with an internal server
* HTML and plain text editor for creating messages
* RSS Feeds
* Reporting features such as bounce-back, opens, and link click reports
* Tracking abilities such as tracking who has opened the email, usually by using a web bug

Opt-in e-mail advertising, or permission marketing, is a method of advertising via e-mail whereby the recipient of the advertisement has consented to receive it. This method is one of several developed by marketers to eliminate the disadvantages of e-mail marketing.

Opt-in e-mail marketing may evolve into a technology that uses a handshake protocol between the sender and receiver. This system is intended to eventually result in a high degree of satisfaction between consumers and marketers. If opt-in e-mail advertising is used, the material that is e-mailed to consumers will be "anticipated". It is assumed that the consumer wants to receive it, which makes it unlike unsolicited advertisements sent to the consumer. Ideally, opt-in e-mail advertisements will be more personal and relevant to the consumer than untargeted advertisements.

A common example of permission marketing is a newsletter sent to an advertising firm's customers. Such newsletters inform customers of upcoming events or promotions, or new products. In this type of advertising, a company that wants to send a newsletter to their customers may ask them at the point of purchase if they would like to receive the newsletter.

E-mail marketing (on the Internet) is popular with companies for several reasons:

• A mailing list provides the ability to distribute information to a wide range of specific, potential customers at a relatively low cost.
• Compared to other media investments such as direct mail or printed newsletters, e-mail is less expensive.
• An exact return on investment can be tracked ("track to basket") and has proven to be high when done properly. E-mail marketing is often reported as second only to search marketing as the most effective online marketing tactic.
• The delivery time for an e-mail message is short (i.e., seconds or minutes) as compared to a mailed advertisement (i.e., one or more days).
• An advertiser is able to "push" the message to its audience, as opposed to website-based advertising, which relies on a customer to visit that website.
• E-mail messages are easy to track. An advertiser can track users via autoresponders, web bugs, bounce messages, unsubscribe requests, read receipts, click-throughs, etc. These mechanisms can be used to measure open rates, positive or negative responses, and to correlate sales with marketing.
• Advertisers can generate repeat business affordably and automatically.
• Advertisers can reach substantial numbers of e-mail subscribers who have opted in (i.e., consented) to receive e-mail communications on subjects of interest to them.
• Over half of Internet users check or send e-mail on a typical day.
• Specific types of interaction with messages can trigger other messages to be delivered automatically, or other events, such as updating the profile of the recipient to indicate a specific interest category.
• E-mail marketing is paper-free (i.e., "green").
• Tracking and response metrics enables tuning and optimisation of the E-mail marketing channel by a process of testing different variants and calculation of statistically significant results.