Iron Man is about technology. In the movie, he's also very specifically about the corporatization of technology, and the responsibility creators have over their creations. But he also represents a general conversation about the role and effects of technology.
In Iron Man, technology has a dark side. In the movie, Tony Stark creates the suit, but he also creates the villains he uses it to battle. And in the comics, Iron Man's suit has, on occasion, become a villain in its own right.
But Iron Man is a superhero. He's technology personified, and, for the most part, he's a force for good. The wrongs he has done, even inadvertently, he works to right. Technology is a powerful tool in that fight, and he has a unique control over it.
Which is at the heart of the Iron Man concept. How do we control technology? In what ways does it affect us? Tony Stark has a remarkable talent, but he simultaneously depends on technology to survive. His injury was inflicted by a man-made weapon, but another device keeps it from killing him. He uses technology to do good, but the evil he fights is often similarly empowered.
And, of course, it's not just shrapnel in his leg or his liver or something. It's his heart that has shrapnel and a magnet in it, magnifying its importance in both physical and metaphorical terms.
"Technology" isn't the only thing that Iron Man is about. And being "about" things isn't the most important thing about Iron Man--the most important thing is smashing bad guys with fancy gadgets.
But what he's about is important. Superheroes, and other culturally important stories, give us a window into our culture's collective unconscious.
Technology is very much on our minds.