First of all all, Obama has a huge following, but he has no real clear plans yet, but is viewed as a messiah for change. Okay, maybe a few and he is not President yet. And no, I don't think he is Hitler, but he does have a demoagogic tendency though. One thing to point out is that Hitler was seen as a messiah who would help Germany, which was Weimar Republic at the time, and he had good intentions.
Godwin's Law in action. Godwin's Law does also apply to Stalin, Mao, and Bin Laden/September 11 Terrorsts. Also, I've the seen name Hitler thrown around in non-political instances, like calling the Florida school teacher Wendy Porillo, "Mrs. Hitler", "Mini Hitler", or "worse than Hitler". Or lumping Lori Drew with Hitler, Stalin, and 9/11 Terrorists.