If your form is multi-page, then it's easy to see how dynamic rendering of fields and drop-down boxes can be used to customize future pages based on customer input. Even simple data-enabled HTML forms can create custom experiences through the order of the questions and the language you use for each segment.

Keep your form short and easy to navigate. Always collect the email address first, and then ask for interests and demographics, letting the prospect know why you need the information at each step. Be sure to include a link to your Privacy Policy or a statement (if true) that "we will never spam you."

Use a "progress bar" to show how much longer the form is, or how far the participant has come in the process. This helps reduce churn. For very long forms (20 questions or more), consider placing a "save now" or "remind me next week to come back and finish" button at regular intervals, so that folks who are tired or distracted can save their partial data. You can let them know on the form and in the reminder email that they won't enjoy full benefits without filling in the entire form.

Customizing language
Use segment identifying questions (gender, job title, purchasing power, interests, et cetera) to create unique paths, and customize the language as you learn more about the prospect.

Speak to mothers differently than expectant mothers, to men differently than women, to urban dwellers differently than suburbanites. Send business prospects down a different path than consumers, or influencers (i.e., CFOs) down a shorter path than decision makers (i.e., IT directors).

HP does it right
Hewlett Packard’s Technology at Work email program requires each subscriber to fill in a three- to four-page form. The value proposition promises subscribers a customized newsletter, specific to their hardware and product use. At each stage of the form, each selection dictates the next set of questions. Select a specific printer, and all subsequent questions should speak to the utility, software and accessories for that printer. If the subscriber indicates a future purchase is imminent, another set of questions is triggered to help Hewlett Packard send relevant promotions.