If you want songs in your profile you must to create a playlist with some web like Playlist.com(Only For U.S) or Mixpod.com( Sorry, it shut down) and get his embed code and paste it in your media box. Maybe some guys would tell you a way for putting a playlist on your profile. I only know that way.
If you want to put some video, just go to the video that you want on Youtube, click on Share>Embed, and copy and paste in your media box
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Somethings like Shout Box, ask to someone.
This is just a little introduction about how to customize your profile. If you want to learn more, ask to that people who knows how to do it.
I think that this post will help you a little bit, and maybe I have forgotten some things but I hope that others user will help you too.