Right now, the first two hits for a google image search on "tiananmen" give you photos of this:
People seem to prefer to decontextualize this image. Dropping the context makes sense: you know immediately what the picture means anyway.
Nevertheless, the decontexutalization bothers me. My difficulty isn't just that no one knows who this guy was or what happened to him. I know that the anonymity contributes to the symbolisism and can live with that. The thing that bothers me is that you rarely even see the end of the video. Some people hustle this man away. First there is a guy on a bike, then a man in a blue shirt, and then a man in a black shirt with his hands in the air. Finally two guys in white shirts come out, but they don't even need to run all the way to Tank Man because the others are pushing him off.
As far as I can tell, no one has posted this video unedited to the web. You can watch it on Frontline, interspersed with commentary. There are plenty of versions of it on Youtube with the end missing, generally overdubbed with protest music. The video should just be put out there to speak for itself, though.
Tank man did not fight against the people who dragged him off. Why?
In a better world, Chang'an avenue would be blocked off for keeps, and they'd put up a statue of a man with a couple shopping bags standing in front of a column of tanks.
In the Frontline video, a professor at Pepperdine comments that Tank Man did not bring down the CCP, but he did help down the Soviet Union. Before the Berlin wall fell, activists in eastern Europe said, "if that kid in China stood in front of those tanks, we can do what we're doing."