Given that you're an unknown commodity, they use your previous salary to determine how other companies valued you.
Between 2001 to 2006 my salary went from 60k to 94k
2006 to 2008 I took a job at a "hot" startup and went down to 89k in return for options (I am never doing that again for a company bigger than 5 people).
2008 to 2012 I took a job that started at 95k, and I've only been able to drive the salary up to 103k even though I've gotten the highest rating possible on every performance evaluation (and I've been a key contributor to hardware development worth about 50 million in revenue -- when other products are breaking even / losing money).
I feel that the only way I can advance my current position is by getting other job offers, but I don't want to be that guy.