On all the Windows there is an option to send feedback.As I appear to have one of the generic activation keys, how will this feedback be attributed to me ?

It will not. As far as I can tell all feedback goes into a general pile. The files automatically submitted with the feedback should have your hardware profile and installed software.

Has anyone found out yet what difference having a key makes at all regarding the feedback tool?

My feedback (that's all over) does not allow me to send it, it's complaining about not being a Connect user who can. Ok Microsoft i have some feedback, but if you want it!

http://timheuer.com/blog/archive/2009/01/12/give-feedback-for-windows-7.aspx