I used to visit justin.tv a lot in the early days, they used to have more interesting people broadcasting but the quality declined over the last 5 years. A lot of the more premium channels/brands broadcast on other sites.

This is reflected in the traffic, just look at the decline from a peak in late 2009. Looking at this graph, it's no real surprise that they are shutting it down:

https://www.quantcast.com/justin.tv#!traffic (click all below the graph)

They have done really well to develop the gaming side on twitch.