Email marketing has been one of the most cost-effective and popular methods of digital marketing since the internet boom of the 1990's.

There are many different ways that companies can use email marketing. Software companies, for example, sometimes mail links to customers so they can download trial versions of their product or use it as a combination of after-sales support and product promotion. Retailers sometimes mail promotional codes and vouchers, whilst other businesses and organisations may simply use the medium to keep consumers and customers abreast of new developments.

However, it is used though, email marketing fulfils a valuable niche in the online marketing sector - the direct method. Like traditional mail, email marketing is a form of direct marketing - sent straight to the consumer without the traditional formal channels of advertising.

It has several advantages over traditional direct mail. In 2007, Pew Internet estimated that on average, half over internet users check or send email on any typical day. It remains one of the most popular daily activities among all internet users and usage has grown year on year even with the introduction of social networking sites.

There are also other benefits in terms of the logistics of marketing campaigns. Firstly, email marketing is one of the most effective methods of marketing in terms of trackable Return on Investment (ROI). Conversion rates can be easily recorded and the most effective methods of marketing identified and utilised. Secondly, advertisers can reach a huge number of subscribers on subject specifically interested in their products at an extremely low cost in both money and time via marketing software.

Still, the biggest benefit of email marketing is that messages can contain the 'call to action' which lies at the heart of direct marketing at the same time as making it incredibly easy for the consumer to act. The simple act of embedding a link within a message can make it as easy as one click of a mouse for a consumer to be taken directly to a product's point of sale or at the very least, to the company's home page. When combined with promotional offers or more advanced designs such as integrated animations or video, the medium can be extremely effective.

Despite the bad reputation and proliferation of 'spam' (unsolicited messages), email marketing is usually what's known as a "permission based advertising" medium. Generally customers give their consent to receive email marketing via company websites or when purchasing products online. Marketers then add them to a database of opted-in contact information - depending on their capture method, they can even segment them according to different demographics.

This tactic has several essential benefits. Firstly, permission based advertising is far more likely to be positively received by consumers; if they have consented to receive it, the chances are much higher that they will read the message itself rather than simply delete it without looking. Secondly it opens up the possibilities of advertising partnerships between different companies; businesses with a complementary target audience can purchase advertisements in other company's emails, such as in the newsletter of a magazine or newspaper. This allows them to reach a specific audience of people likely to engage with their product.