I think of it this way... companies get complaints 24/7. If you release your product out to millions of people, more than likely someone is going to have a problem with it and want to tell you about it. If something bad happens to you, the first thing you want to do is tell someone else. However, if a product works as it should... usually that's not really big news.
But these companies work hard on their merchandise and are working to improve it every day. Don't they deserve some good feedback, where good feedback is deserved?
So I started writing different companies that made items that I use daily around my home and let them know how much I appreciated their hard work. The response was more than worth it. I have gotten coupons, freebies and thank-you gifts in the mail or through my email! My favorite was probably S.C. Johnson when I wrote to them about how much easier Windex made my life. They sent me a coupon for a free bottle of Windex and a booklet of other $1 off coupons for all their other merchandise.
A friendly word can go a long ways.
Have you had any success getting free stuff or coupons? If so, what did you do to get it?