Yes, giving feedback is very important if you want something from a service. We don’t have any right to raise our voice against anything if we don’t ourselves try to make it better. I came up with the idea of this point because few minutes back when I opened my Gmail, I saw a link asking for Feedback survey. Maybe Google wants to check the response of newly launched Gmail Interface (the so called Gmail 2.0)
If you will not give feedback, how will a company know what you don’t like in its product or what you like. Its not to us, whether the company takes a survey seriously or not(Google Takes seriously though), but our job is to make a company realise the pros and cons of its products. This happened recently when Yahoo! launched Beta version of their latest messenger and people didn’t like its interface or complained that it removed lots of features. Instead of making a hue and cry, give them feedback via the official feedback channel provided by the company. Just check now, yahoo did listened to a lot of feedback and have improved a lot.
So, if we don’t like widgetbucks, keep sending them mail to improve, check for alternatives. I did contacted them. You also do. And now don’t forget to give Gmail 2.0 its much needed feedback. 
Generally speaking a good point , we’ve all become so cynical of marketing type data collecting , that’s it’s easy to be blind to genuine requests for feedback
As a person running an internet company, I adore the people who take the time to give me feedback. I depend on them to make my service better. And when I hear from someone, I jump, because I figure for every person who took the time to call or email, there are 20 who thought the same thing and did not make the effort.