The most common infringment of the fair use clasue was failure to give citation of the media used in the video clip of oprah they also failed to apply it to any form of teaching. The video on classroom rules used the music from vanilla ice and never cited him as the original composure which some argue he stole it anyway so it is just fair game. I think the most common thing is people forget to cite the media used although we dont need permission to use it we do need to give credit to the original.