It's been said before, but important to re-emphasize, e-mail is the "killer application" of the information age. According to the latest Forrester Research numbers, the permission based e-mail industry is projected to grow from $164M (USD) in 1999 to $7.3B by 2005. E-mail is also rapidly moving from a textual communications process to one that is rich in multimedia content via server-based streaming audio or video. Virtually anyone, even those with extremely low bandwidth, can now view compelling content.

Here is a condensed primer for developing an effective opt-in e-mail campaign:

1. First and foremost, what is permission based or opt-in e-mail and how is it distinguished from Spam? Opt-in or permission based e-mail (the terms are interchangeable) means recipients have confirmed their interest in receiving e-mail and have signed up (hence the term opt-in) to receive e-mail about a subject of their interest. The recipient may also unsubscribe from the list at any time and all e-mail messages are clearly identified as coming from a specific and approved vendor or source.

2. We do not recommend Spam (unsolicited bulk e-mail messages) to our clients, nor have we ever developed a campaign that is not opt-in based. We think there is a growing backlash to Spam and many of us (author included) are inundated with it and delete it as soon as we recognize it.

3. The actual opt-in e-mail content is very important, like any interactive marketing process. The subject itself needs to be succinct and informative (as this is how most people filter e-mail), the text in the message should be concise, with paragraphs no more than 2-3 short sentences, customer references should be referred to in the lead paragraph to drive the rest of the message, have no more than two hyperlinks embedded in the content, and utilize a close and signature that thanks people for their time with a link (phone and e-mail) to a "real" person.

4. Many marketing types don't know whether to use HTML (rich media) or textual content. A standard rule of thumb is, if your target audience is consumers, then many prefer the HTML format, due to the snazzier graphical content; but, if you are targeting corporate or technical types, the majority of them want a message that is text only and one that leaves out any/all marketing hype - just the concise facts.

5. Costs can vary dramatically depending on your target demographics or market segment. A good rule of thumb is to expect rates of $.05 (USD) to $.25 per message, depending on the size of the media buy and frequency (the number of times you are using a list), type of list demographics, vendor selection (small publisher versus comprehensive services provider such as YesMail), and market conditions in the interactive advertising market.

6. What should a good campaign generate in terms of response rates; i.e., those that clicked through from your message to a web site or called a toll-free number? These numbers will fluctuate based again upon your market segment, product or service you are selling, type of response rate you are seeking (download, e-commerce sale, review of materials via a web site, etc.). But, industry averages are from 4% up to 20%. Unfortunately these numbers are going south as more and more companies integrate opt-in e-mail with interactive and offline marketing processes.

7. Message testing is also a very important component of this process. Meaning, you need to develop 1-3 messages ("creative" in marketing speak) that have different content and call to action components. Then test by utilizing 10-15% of your total media buy by sending out these test messages and assessing the response rates and go to market with the message that generated the highest return. Be forewarned, this process can slow the campaign down, but testing can help you increase your response rates or back end ROI exponentially.

8. Your interactive ad agency or list partner should help you setup "landing page(s)" - the actual page where people are taken via a hyperlink in your opt-in e-mail message. This page should have content that is integrated with your opt-in message and act as a response mechanism by capturing sufficient information to enable you to build your own in-house newsletter, which in turn helps to leverage downstream media costs.

9. Finally, the last and most important part of the process is setting up tracking reports that will enable you to carefully analyze the results from your opt-in e-mail campaign. This is typically done by inserting 1-2 lines of HTML code on 3-5 pages of your web site (product overview, registration, or home/index pages for instance). A report can then be generated that shows the number of respondents for each page as a subset of the overall response rates from the campaign. This critical analysis process will help you understand the effectiveness of your overall campaign and will also provide valuable insight about your web site content, UI (User Interface) and navigation.