dubbing vids with new music
 

Is this a good idea for videos without any tunes? I'm sure it depends on the site, but I'm debating it right now for my under construction paysite.

tunes as in what? copywritten material on a radio in the background? what kind of videos?

nah, just free license stuff - just like a appealing background track on some general softcore stuff for embedded flash videos, maybe even give the user an option between a few tracks