Pinecast is powered by Amazon Web Services on the back-end, meaning content is stored and distributed with the same technology that powers world-class services like Netflix. Pinecast's web servers are powered by Heroku (which is backed by AWS), and is monitored by two separate failure and error monitoring tools.
The Heroku application has redundant instances with three workers each. Each instance should provide redundancy against failure across any of the others.
Pinecast's services are also distributed across separate hosts. Analytics are hosted separately from the GeoIP server, for instance.
Because of all of this, Pinecast outages are quickly detected and resolved. Pinecast currently provides no SLA, but uptime is generally 99.99% or better in any given month. If Pinecast's web servers experience an outage, audio can still be downloaded by subscribers in apps like Apple Podcasts and Google Play without interruption.
You can see Amazon's service status page here: http://status.aws.amazon.com/