ESPN Mobile announced yesterday that they will cease operations of their MVNO. See story.
Most of what I have to say about the challenges of an entertainment-oriented wireless carrier are in a posting from this summer. It's more of a case of being overambitious than failing – it would have been very hard to succeed without a very low cost base. It's better to exit than stubbornly pour more money into an operation and business model with so many challenges.
In any case, it certainly isn't their exit from the mobile industry. I'm sure they have learned a lot from the experience and will benefit as they sell their content to other carriers with a larger subscriber base.