Awesome way to market through social media

Hey,
So recently a lot of music artists/bands in Australia have been releasing music online before physical distribution (if they physically distribute at all) and have found an awesome way to penetrate their target market and create a viral buzz. They set up a website for themselves where their fans can go and download or stream their new song or video. But before the fans can access the new material they need to enter their facebook or twitter user name and password and agree to let the site promote through their account. So every time someone downloads the song or listens to it or watches the video online, a tweet is automatically sent from their account or a link is sent through their fb page with a message saying "listening to (band name)'s (song name) for free, RT" or something similar to that. This may seem very small and insignificant but actually has a huge impact on the traffic to the site.

When one person does it, that message reaches all of their social network contacts of which a few are bound to do the same and it begins again. When some of the bigger bands release something, my facebook and twitter time line is often completely flooded with messages about what ppl are listening to or watching. This way of marketing is effective, virtually free, has a sense of credibility as it is coming from friends and peers and has the potential to snowball and get very big very quickly.

Here are some recent, bigger examples of what I'm talking about.

http://www.heroesforhire.com.au/

http://www.theamityaffliction.com/

Check them out :)