Can someone explain to me why they think Obama compares to Hitler?

I just don’t get it? I am not asking this question to argue about health care, or the TARP money, or any of that. I just really don’t get what Obama and Hitler have in common. Hitler used propoganda and fear to convince the public to go along with him. He was a genocidal maniac who believed there was an elite race. Hitler also wanted to take over Europe and probably the world. He carted around human beings like cattle, stealing their property, and enslaving people. How does this compare to Obama?