Community incentives can take many different forms. If your visitors have profiles that are visible, some type of title or other indication of a particular community member's participation in the community. It might also be possible to provide them access to certain special features. For example, since these individuals have expressed an interest in helping the growth and development of the community, you could have an extra forum for development suggestions. Only those community members who have filled out the survey would have access to it.
So there you have it. You now have some information about some of the many ways you can listen to your website audience's wants and needs. From a very basic contact form all the way to a detailed survey, you have many options at your disposal. The complexity of a detailed survey brought about a discussion of just how you're going to make your survey visible to your community. Finally we covered several methods of motivating your website's visitors to complete an online survey.
The techniques discussed here are all suggestions. Some may work for you, others may not. If you can come up with something more creative I encourage you to pursue it. In any case, it's important for you to understand the value of listening to your audience. They will help steer you in the right direction, you just have to ask the right questions, listen to the answers carefully and interpret them properly.