If you have a blog or website, make sure you allow comments. You can learn a lot when you let people talk back. Big businesses pay lots of cash to get feedback from their customers. Comments are free.
If you are afraid of what people may say, you can always moderate your comments or approve them before they go live on your site. I recommend you allow people to comment without screening them. Even if they say something negative, it shows you have nothing to hide.
Don't have a blog or website? Use a comment card. Give them to your employees too.
Where can you allow comments?