Many gamers will point to some video of a game on Youtube, and go "Look at how great the graphics are, this is so much better than game . In your face 360/PS3/PC gamers (delete fanboys platform of choice). You've lost.".
This always makes me laugh for a number of reasons:
A lot of those videos are pre-rendered. They might be the intro clip, or other movie clip, not actual gameplay.
Youtube isn't exactly known for it's high quality. Most of these videos are encoded on the default quality. If they come from the company, they might just be high quality, which is still inferior to the video quality actual gameplay on whatever game they're saying it's better than. To see just how bad it is, look at the pictures from this blog post.
And remember, most games nowadays are 720p, twice the quality of the second picture, and scaled up to 1080p by your console, nearly 3 times the quality if you have a full HD telly.