Anything on the web can be copyrighted and there are ridiculously complex laws governing how these items can be used. This means songs, movies or photos. The web and new software has made it very easy to take things that are on the web and use them in new ways, then distribute them and share them all over the web. There are many websites such as flickr, spotify and torrent which allow music, videos and photos to be sen and shared with everyone. Things can be taken from these sites for free and reused in a different way. Songs can be remixed and put on Youtube, indeed they make up a large proportion of the videos on youtube. The companies who want to make money out of these songs get very cross as their copyright laws say that the songs can't be used like this. There has been many legal cases taken to court about remix and mashups. The most famous is the case of Shepherd fairey and A.P, a company whose photo was reused to make the famous Barack Obama HOPE poster by Shepherd Fairey.
Mashups are quite common and they can be defended in court by saying that they used the item with 'fair use' which means that they did not use it in a way that would make it seem worse or change the value of the item. If the remix actually promotes the product then that can be argued as well.
I think that people should respect the copyright laws but they should still share their remix but with a reference. I beleive that sharing is good and the way forward.
