Another option you can pursue to help gather information about your community is to use a larger, multi-question survey. With this approach, you can get detailed feedback in a shorter time span. The problem will be both exposing this survey to your community and motivating individuals to fill it out. Your survey will likely require more time and effort from your visitors than having them send you an e-mail, so how will you motivate them?
First off you have to make your visitors aware that there is a survey in the first place. There are basically three venues at your disposal.
The first strategy you can employ to make your survey known is to flat out spam. It's not a terribly effective method because it's not necessarily targeted towards your particular audience. Recent court rulings have also made it a dangerous endeavour indeed. I would not reccomend this approach.
The second strategy is to notify your audience via e-mail. In order to prevent this from becoming spam, your visitors must have opted in to receiving e-mail from your site. This kind of mailing list takes time and forethought so you may not have this valuable resource at your disposal.
If you don't have an opt-in mailing list put together, you'll have to use your website itself to make all of your visitors aware of your survey. You can use whatever method you feel is most appropriate for this. You can make a big one-time splash on your main page, consistent promotion across the entire website, long term integration into the website structure or even just talk about it on your forums.