What are the legitimate uses for BitTorrent?

I dusted off Transmission this evening, updated it to the latest version and took it out for a spin. I am tormenting Ubuntu 11.10 just to see how effective BitTorrent can be as a file sharing service. Its great, works beautifully thanks to the many people who are seeding the file and that is one of the catches. When it works well, it works brilliantly.

Of course BitTorrent is pretty popular with those who prefer not to pay for content like TV shows and movies but I have to wonder if there are effective and legitimate uses for the technology? I suspect a number of apps and services uses BitTorrent under the hood and that isn’t always transparent to users but where else is it used effectively?

I also started thinking about some potentially interesting uses for BitTorrent. Imagine an artist seeding albums using BitTorrent? Actually, you don’t really need to imagine that as a hypothetical. NIN did that with Ghosts a while back. Imagine if smaller artists started seeding their albums and changing their revenue model. Its probably being done somewhere and I’d love to know how that works. There must be other good case studies?