Forms are a great method to collect information from visitors to a Web site, but they are not the only method. An alternate means, such as an e-mail address and a phone number, should be provided since there are some situations where form technology may not be fully supported. If the user can send an e-mail, then why complicate things with a form?
Forms allow a Web designer to guide the information sent by the user. For instance in submitting a question to Tech Support it is important that the person include their name, phone number and helpful if they also include their status. The form will encourage or require them to provide the necessary information, while an e-mail or voice mail message can not.
Of course, forms are the best way to conduct online surveys and registrations. It can restricts the answer provided by the user so that the results are more quantifiable.
As long as an alternative means for users with disabilities or other technological reasons make using forms difficult, forms are the perfect answer for collecting information from Web visitors.