Re: what is your desired salary?
It's a common question, and someone who has say 5+ years of experience in his/her domain of expertise is entitled to make a decision based on salary information.
For new grads, the intention in such questions is to gain a sense of how much you know your industry... study salary surveys / talk to ppl etc. and during the interview process, if and when asked, emphasize that you're flexible but portray that you've done your research.