Maybe I misunderstand what getsatisfaction is.... could I go there are report a bug on hacker news for example even if hacker news have not joined getsatisfaction?
Yup - you misunderstand, and yes you could just report something for a company that's not joined getsatisfaction. A chunk of people see this as a bad thing - see http://37signals.com/svn/posts/1650-get-satisfaction-or-else and http://sachin.posterous.com/get-satisfactioncom-is-blackmail... for example.