The google translator for markups. From my point of view, Some actual features or interface design options from this Google translator could, may be, inspire you as well. :)

That's an insightful analogy. I hadn't really thought about it that way, but you are absolutely right. I'll keep that in mind.

Great! but interface is a bit confusing. i still do not understand it fully. :(

Thnx! Yes, UI is a pitty one, I could use some good advice on that.

Main problem: I'm trying to combine the 'MTV functionality' with the original functionality of listandplay.com (generate playlists in a few clicks). I thought about splitting up both projects, but I want to avoid that... What would you do?

I really think it should be as simple as possible. Split both projects.

Your UI could be just a search box, where you enter the artists name, and the App then creates a continuous stream of music videos. Not more, not less. Maybe add the Skip button and count (server side) how often a video has been skipped, to create a "blacklist" of bad videos, that won't show up anymore.

Look at the UI of http://www.mixest.com/ for instance - I think they nailed it.

??? why pointing out such article?