When you contact someone/make a request/post a comment etc etc through a website form you are likely to be seeking a response- otherwise why bother? It could be that (e.g.):
-someone will get back to you
-your words will appear on the site
-you'll get to download that plugin you've been jonesing for

...whatever the response, it is utterly reliant on the form mechanism.

Forms can be great- if they're well constructed, meet the expectations of your visitor and actually work that is. For example they can increase your conversion rates, get you talking with more people, give you a managed distribution platform, gather information etc.

However (you knew that was coming, right?), a bad form is worse than none. Typically a bad form is one that allows you to submit it with null data, or is too long, or is not intuitive, or doesn't let the visitor have a (little) bit of leeway over what they can enter (e.g. restrictive address fields).

I'm an advocate of the humble form, and regularly sing its benefits to clients. For many business models it can be the precise measure of a site's success. In the right circumstances if you calculate the amount of times a form is submitted and how much revenue was brought in as a direct result you can figure out the ROI of a site. More common is that a filled-in form shows the effectiveness of the SEO work that brought the visitor to that page, and the effectiveness of the page itself.

The SEO benefits of website forms are that they can allow us a clear measure of what is effective and what is not.

But how do you create a form if you're not a web developer? You don't. You let someone like WuFoo do it for you. This particular example offers great customization and integration options, and it appears to work well.