Community engagement is an ongoing challenge for managers. As content curator, you want to ensure members are actively participating and keep coming back. A community feedback survey is one sure measure to understand where improvements or new interests can be developed further (see King Arthur Flour's story).
Collecting feedback is essentially the same approach whether you're managing an intranet portal or external member community.
Here are five steps and quick tips to design a survey and collect feedback using Google Docs. There are other survey tools you can use, and possibly your collaboration productivity tool includes a template.