Mash Up: Every Girl's Dream?

At last! After hours of working and waiting I’ve successfully uploaded my mash-up! To my surprise Youtube didn’t allow my efforts to be seen on the web. Apparently, FOX claims that they own some of the materials I used. Before uploading, I observed how other users get away with using the works of different “artists”. Many indicated the statement “I do not own anything” on the description box of the recreated work. But I don’t understand why it didn’t work in the case of my vid. I even typed my sources in the said box though it was already incorporated in the video.
Also, I saw that there are materials where users neglected to name their source or the original artists, especially for songs used in slide show presentations. But these uploads were not blocked. I assume that a lot of these users are not associated with the artists or copyright owners of the work. If this assumption is correct, does this mean that they had to pay the copyright just so they can come up with a 2 to 3 minuter that aids audience to learn the lyrics of songs or maybe even just for the heck of making one? I think this lopsided process of halting materials points us to the issue of ownership. A big company such as FOX could easily take measures to safe guard their products as well as the supposed profit they can obtain from it. But come on, I don’t expect to dig up anything monetary from their product.
Forming the rules and laws that will oversee the interaction in the cyber world is still a struggle for business industries, creators and the aspirants. But since there are those who stand that the rights they hold to their products when positioned in the tri-media be also translated in the same manner on the internet, wouldn’t it be rational to also carry the “privileges” granted for certain groups (and purposes) such as the academe to access and handle these materials for no or minimal cost?
The magnitude of what new media holds still seems too big for industries that loaded and matured with the aid of the first three media. Finding their place in this new playground is tough for many of them as the nature of this medium swaps the grasp of power.