Listening to music online

I don't understand your question. What are you trying to accomplish with online music? MP3 is much better than streaming however streaming is the format used at the sites you mentioned. They are only trying to give you a sample of what the song sounds like, not its quality What is your objective?

Eldon; I am not an authority on the subject matter at hand but I do know enough to maybe get you started. The streaming that I heard does sound horrible. MP3 is a compression format which is the format used at places like Napster and some newsgroups. Generally the higher the bitrate the better the sound. Bitrates range from 64-320. There is also a variable bitrate which is the best.
I'm not familiar with streaming technology but I have an idea that the bitrate is very low thus poor recording. However because its file size is small it is faster to download. You might be able to make samples in mp3 format but your listeners would have to have an mp3 player to play the sample. There are free mp3 players for download. You could put a link to the free players. However keep in mind, the better the quality the larger the file and the slower the download. 192 is probably the best bang for the buck.
I don't know if this has been helpful to you. As I said, I am no authority.