Mash Up is like a song or composition created by blending two or more pre-recorded songs, usually by overlaying the vocal track of one song seamlessly over the instrumental track of another.
When a Mash Up is good is because they choose the right songs for the rhythm,also because they know how to do a Mash Up and with the experience of hearing song.
When a Mash up is not is because the song are completely different and dont match at all, also when the rhythm is different.
This is one example of a good Mash Up
http://www.youtube.com/watch?v=MT5kwJVwru8&feature=fvst
This songs I also listen to them, but I mostly listen to this one because its a very good Mash Up
http://www.youtube.com/watch?v=iNzrwh2Z2hQ
I think Mash up people like the person who make these mash up, are like artist because they make pretty good songs but the person who make mash up but the song is lame, I wouldn't considered as a artist.
