Joost died because it didn't do what it said it did: Let you watch TV on the internet.

It let you watch little snippets of things you weren't interested in. I downloaded the client because I lived in Spain at the time without a television. I tried to use it a few times, but there was never anything on it worth watching. Certainly no network television. None of the sports that it promised. Basically, nothing at all to watch.

Then Hulu came along with a thing that let you watch TV on the internet. The rest is history.