One of the possibilities could be that Google is prepping up a new music based website. A Google Site query reveals that Listen.in was previously a music based social network where you could check out what your friends are listening to, in realtime, along with the ability to connect your playlist with your friend’s playlist and the domain was previously registered to a Robert Kim of Toronto, Canada.
The search result also reveals a couple of album listings and a download page but sadly, none of them are accessible right now. Hence I am not sure if you could listen or download music from the portal earlier.
Another possibility is that Google could use it for its Indian version of Google Music search which was launched in beta last year or a web version for Google Listen, where Google could highlight the popular podcasts, offer users the ability to manage them and so on. However, I am highly skeptical about these.
That said, all of the above possibilities are just our educated guesses and we might be completely wrong about it, but it would be interesting to see what Google is upto, especially now that Google Music has been launched officially.